According to the Nichiren Shoshu and SGI the Lotus Sutra is no longer valid in the Latter Day

“The meaning of this passage is that those who obtained benefit during the Former and Middle Days of the Law received “conspicuous” benefit, because the relationship they formed with the Lotus Sutra during the lifetime of the Buddha had finally matured. On the other hand, those born today in the Latter Day of the Law receive the seeds of Buddhahood for the first time, and their benefit is therefore “inconspicuous.” — Nichiren from Teaching, Practice, and Proof

SGI background states:

“..In this letter, Nichiren Daishonin states that Shakyamuni’s teachings no longer lead to enlightenment in the Latter Day of the Law, and that only Namu-myoho-renge-kyo combines the three elements of teaching, practice, and proof essential to making Buddhism viable.”

An SGI member regurgitates this misunderstanding:

“In this passage Nichiren states that those who lived in the Former and the Middle day of the Law were able to attain Buddhahood through their relationship with the Lotus Sutra of Shakyamuni and his disciples who have been born together, their cause have matured as the effect accumulated from past existences therefore their harvested benefit is conspicuous since they share the same heriage. However, those who are born in the Latter Day of the Law are no longer connected to Shakyamuni’s harvested enlightenment and are receiving the seed of Buddhahood hidden in the depth of Lotus Sutra for the first time through the very Law that all Buddhas have attained throughout time and space revealed by Nichiren Daishonin being Namu-myoho-renge-kyo.”

Nichiren, on the other hand, goes on to correct this non sequitor:

Answer: The above-mentioned commentary states that such an interpretation of the last five-hundred-year period is “superficial.” From a more profound viewpoint, the Lotus Sutra will spread throughout the ten thousand years of the Latter Day. The Great Teacher T’ien-t’ai comments on the previously quoted sutra passage, stating: “It is not only the people who live during the Buddha’s lifetime who obtain great benefits. In the last five hundred year period, the mystic way will spread and benefit humankind far into the future.” Does this annotation suggest anything other than the ten thousand years of the Latter Day of the Law? The “Distinctions in Benefits” chapter in the sixth volume of the Lotus Sutra states, “In the evil age of the Latter Day of the Law if there is someone who can uphold this sutra . . . .” Also the “Peaceful Practices” chapter reads, “In the Latter Day of the Law, if one wishes to preach this sutra . . .” These quotations refer to [the propagation of the Lotus Sutra in] the ten thousand years of the Latter Day of the Law. All the Buddha’s teachings other than the Lotus Sutra are covered by his declaration: “In these more than forty years, I have not yet revealed the truth.” Moreover, there are some cases where the sutras have been revised according to the understanding of those who compiled them and therefore cannot be trusted.”

SGI and the above mentioned SGI member have revised the teachings and can not be trusted. Let us look at the most important Gosho, The True Object of Worship to see if what SGI teaches accords with the mind of Nichiren:

“People can attain enlightenment in two ways: by meeting the Buddha and hearing the Lotus Sutra, or by believing in the sutra even though they do not meet the Buddha…” [Writings of Nichiren Daishonin page 359]

Nichiren goes on to say:

“It is evident that the Revelation of Eternity was preached for the sake of those who live at the beginning of the period of Deprivation. In this respect, we are as fortunate as those who heard the Buddha in person, the difference is, they brought to fruition Buddhahood by hearing the ‘One Chapter and Two Halves’, while we are endowed with the seeds of Buddhahood by receiving the Five Words.” (Five Major Writings of Nichiren, Kanjin No Honzon Sho, NOPPA pg 370)

Again, we see that it is always the Lotus Sutra that leads to Enlightenment but the practice of the Lotus Sutra differs according to the age. The seed of Buddhahood is always Shakyamuni Buddha's Myoho renge kyo [Lotus Sutra]..

The practice of the Lotus Sutra in the Latter day is Namu Myoho renge kyo, not singing silly songs to Sensei or deprecating the Lotus Sutra by teaching that it is no longer valid in Mappo.

"I have accordingly quoted the passages from the Lotus Sutra that read, 'In the evil age of the Latter Day of the Law if there is someone who can uphold this sutra . . . ,' 'in the latter age hereafter, when the Law is about to perish . . . ,' and 'they [the Buddhas] make certain that the Law will long endure' in order to demonstrate the error [of believing that the Lotus Sutra has lost its effectiveness]. " -- Nichiren

But in order to assert that the Lotus Sutra has lost its effectiveness, the SGI often cites the following passage from Reply to Lord Ueno:

"Now, in the Latter Day of the Law, neither the Lotus Sutra nor the other sutras lead to enlightenment. Only Nam-myoho-renge-kyo can do so. This is not my own judgment. Shakyamuni, Many Treasures, the Buddhas of the ten directions, and the bodhisattvas who emerged from the earth as numerous as the dust particles of a thousand worlds have so determined it. To mix other practices with this Namu-myoho-renge-kyo is a grave error. A lantern is useless when the sun rises. How can dewdrops be beneficial when the rain falls? Should one feed a newborn baby anything other than its mother's milk? No addition of other medicines is needed with a good medicine. Somehow this woman remained true to this principle, and continued to uphold her faith until the last moment of her life. How admirable, how worthy!

With my deep respect,

Nichiren

The first day of the fourth month in the first year of Koan (1278)

The Soka Gakkai takes the Gosho out of context in order to debase the Lotus Sutra. What this does to their believers, their minds of faith, and to the teachings, is unpardonable. 

The One Great Secret Law is Namu Myoho renge kyo. This is the teachings of Soka Gakkai, the Nichiren Shu, and the Kempon Hokke. The Nichiren Shoshu teaches that the One Great Secret Law is the DaiGohonzon. I will leave aside for the moment who is correct about the One Great Secret Law. Every last Nichiren Buddhist, from the newest member to the most experienced knows that there is no practice in the Latter Day other than chanting Namu Myoho renge kyo. SGI's oft repeated argument implying that the Nichiren Shu, the Honmon Butsuryu Shu, and the other Nichiren practitioners, neither practice nor understand the import of Namu myoho renge, is nothing but a straw man argument. It is a logical fallacy.

Lord Ueno is none other the young samurai, Nanjo Tokimitsu. This writing is from 1278 in response to offerings he received from Lord Ueno and in memorium for the death of Lord Ueno's niece. Here the Daishonin is stating that Namu Myoho renge kyo is the practice for the Latter Day. We read in an earlier part of this letter [which SGI members never cite] :

"After Many Treasures Buddha had closed the door of the treasure tower and the other Buddhas had returned to their original lands, not even Shakyamuni Buddha himself could have denied the Lotus Sutra, whatever other sutras he might have expounded in an effort to do so, because the other Buddhas had all joined in affirming its truth. That is why in the Universal Worthy and Nirvana sutras, which follow the Lotus Sutra, the Lotus Sutra is praised but never disparaged. Nonetheless, priests like Shan-wu- wei of the True Word school and the founders of the Zen school have repudiated the Lotus Sutra, and the entire Japanese nation has now taken faith in their teachings, just like those who were deceived by the rebels Masakado and Sadato. Japan is now on the brink of ruin because it has for many years been the archenemy of Shakyamuni, Many Treasures, and the Buddhas of the ten directions, and in addition, the person who denounces these errors is persecuted. Because such offenses thus accumulate one atop another, our nation will soon incur the wrath of heaven."

On the one hand we see that repudiating the Lotus Sutra is a cause for falling into hell and on the other hand we read that, "neither the Lotus Sutra nor the other sutras lead to enlightenment". How does one resolve this seeming paradox? Nichiren Daishonin writes in the True Object of Worship (Kanjin No Honzon Sho):

"Answer: This is a matter that is difficult to believe and difficult to understand. T’ien-t’ai defined two points that are “difficult to believe and difficult to understand.” One lies in the realm of doctrinal teachings and the other in the realm of meditative practice. With regard to the former, in the sutras preached before the Lotus Sutra we read that persons of the two vehicles and icchantikas, or persons of incorrigible disbelief, are forever barred from attaining Buddhahood, and that Shakyamuni Buddha, the lord of teachings, attained enlightenment for the first time in this world. Nevertheless, we find that the theoretical and the essential teachings of the Lotus Sutra repudiate both these statements. One Buddha who says two things as opposite as fire and water— who could believe him? This is the point that is “difficult to believe and difficult to understand” in the realm of doctrinal teachings.

The point that is “difficult to believe and difficult to understand” in the realm of meditative practice, concerns the principle of the hundred worlds and thousand factors and that of three thousand realms in a single moment of life, which explains that even insentient beings are endowed with the ten factors of life, and that they are endowed with both material and spiritual aspects.":

Thus we see that Nanjo Tokimitsu was confused by the Tientai practice of the Lotus Sutra that was prevalent in Nichiren Daishonin's day. The Lotus Sutra is practiced differently according to the time. Here Nichiren is talking about Tientai's Lotus Sutra teachings and practice. The Lotus Sutra itself must never be disparaged, contrary to the slanderous Soka Gakkai teachings. Disparaging the Lotus Sutra is why their members suffer in the Great Citadel of Hell, why Japan is on the verge of ruin, and why their teachings lead people into the Lower Three Worlds.

One can not read the entirety of the writings, especially the Five Major Writings, and perceive that Nichiren Daishonin disparaged the Lotus Sutra. Soka Gakkai practitioners are evil people, according to Nichiren Daishonin. 

In conclusion, for the one or two passages in the entire Nichiren Canon that SEEMS to disparage the Lotus Sutra, there are nearly four thousand passages praising the Lotus Sutra. Here are some examples:

Nichiren on Disparaging the Lotus Sutra and its votaries

"As for the person who slanders the Lotus Sutra, though he may not be serious at heart, if he so much as manifests the outward appearance of animosity, disparages the sutra even in jest, or makes light, not of the sutra itself, but of those who act in its name, then, the sutra says, he will fall into the hell of incessant suffering for countless kalpas of the kind described above." - On Rebuking Slander of the Law and Eradicating Sin

"After Many Treasures Buddha had closed the door of the treasure tower and the other Buddhas had returned to their original lands, not even Shakyamuni Buddha himself could have denied the Lotus Sutra, whatever other sutras he might have expounded in an effort to do so, because the other Buddhas had all joined in affirming its truth. That is why in the Universal Worthy and Nirvana sutras, which follow the Lotus Sutra, the Lotus Sutra is praised but never disparaged." - The Teaching for the Latter Day

"Yet there are Buddhist scholars in Japan today who cast aside the Lotus Sutra and instead devote themselves exclusively to practicing the invocation of Amida Buddha’s name. There are others who teach the Hinayana precepts and speak contemptuously of the priests [who were ordained with the Mahayana precepts] on Mount Hiei, as well as those who present what they describe as a separate transmission outside the sutras, disparaging the correct doctrine of the Lotus Sutra. Such persons may surely be said to misunderstand the time. They are like the monk Superior Intent who slandered Bodhisattva Root of Joy, or the Scholar Gunaprabha who behaved with contempt toward Bodhisattva Maitreya, thus inviting the terrible sufferings of the Avīchi hell." - The Teaching, Capacity, Time and Country

"It was such an august and precious Lotus Sutra that in past existences I put under my knees, despised, scowled upon in disgust, and failed to believe in. In one way or another, I maliciously ridiculed those who, studying the teachings of the Lotus Sutra, taught them to even one person, and carried on the life of the Law. In addition, I did everything I could to hinder people from embracing the sutra by asserting that they should set it aside for a while because, though it might be suitable for practice in their next lifetime, it would be too difficult to practice in this one. Slanderous acts such as these have brought on the many severe persecutions I have suffered in my lifetime. Because I once disparaged the Lotus Sutra, the highest of all sutras, I am now looked down on, and my words go unheeded. The “Simile and Parable” chapter states that other people will neither concern themselves with one nor have sympathy for one, even though one sincerely tries to be friendly with them." - The Sufferings of Birth and Death are Nirvana

"The second of the two important matters is that I feel intense grief. The fourth volume of the Lotus Sutra states: “If there should be an evil person who, his mind destitute of goodness, should for the space of a kalpa appear in the presence of the Buddha and constantly curse and revile the Buddha, that person’s offense would still be rather light. But if there were a person who spoke only one evil word to curse or defame the lay persons or monks or nuns who read and recite the Lotus Sutra, then his offense would be very grave.” When I read this and similar passages, my belief is aroused, sweat breaks out from my body, and tears fall from my eyes like rain. I grieve that, by being born in this country, I have caused so many of its people to create the worst karma possible in a lifetime. Those who beat and struck Bodhisattva Never Disparaging came to repent of it while they were alive; yet, even so, their offenses were so difficult to expiate that they fell into the Avīchi hell and remained there for a thousand kalpas. But those who have done me harm have not yet repented of it even in the slightest." - The Four Debts of Gratitiude

"Is Nichiren not the votary of the Lotus Sutra? Are the voice-hearers protecting those who disparage the Lotus Sutra as a mere written teaching and who put forth their great lies about what they call a special transmission? Are they guarding those who write “Discard, close, ignore, abandon!” urging people to close the gate to the teachings of the Lotus Sutra and to throw away its scrolls, and who cause the ruin of the temples dedicated to the practice of the Lotus Sutra? The various heavenly deities swore before the Buddha to protect the votary of the Lotus Sutra, but now that they see how fierce are the great persecutions of this muddied age, do they fail to come down? The sun and the moon are still up in the sky. Mount Sumeru has not collapsed. The ocean tides ebb and flow, and the four seasons proceed in their normal order. Why then is there no sign of aid for the votary of the Lotus Sutra? My doubts grow deeper than ever." - The Opening of the Eyes

"The claim that T’ien-t’ai stole the doctrine of the five flavors, which is expounded in the Six Pāramitās Sutra, and made it a part of the teaching of his own school, is a charge made by the Great Teacher Kōbō, one that is wholly false and without basis. I say this because T’ien-t’ai in fact derived the doctrine of the five flavors from the Nirvana Sutra, not from the Six Pāramitās Sutra at all. The Six Pāramitās Sutra was not introduced to China until the fourth year of the Chen-yüan p.369era [788], or 190 years after the death of T’ien-t’ai, so how could T’ien-t’ai even have seen it? That completely false assertion is the work of the Great Teacher Kōbō.

All of the statements of the Six Pāramitās Sutra represent the teaching set forth when Shakyamuni had “not yet revealed the truth.” It is utterly absurd to think one can use them to disparage the Lotus Sutra!" - On the Relative Superiority of the True Word and Tendai School

"In the Hinayana sutras, the principle of nirvana of no remainder is “king,” and in comparison to the Hinayana precepts and meditation, the Hinayana wisdom is king. In the Mahayana sutras, the principle of the Middle Way is king. In the Flower Garland Sutra, the principle of the perfect fusion and unity of all phenomena is king. In the Wisdom sutras the principle of non-substantiality is king, while in the Great Collection Sutra the guarding of the correct Law is king. The Medicine Master Sutra is king among the sutras that describe the special vows taken by the Buddha Medicine Master; the Two-Volumed Sutra is king among the sutras that describe the forty-eight vows of the Buddha Amida; and the Mahāvairochana Sutra is king among the sutras that describe mudras and mantras. But none of these is the king of all the sutras preached during the Buddha’s lifetime. The Lotus Sutra is the great king of all the ultimate doctrines expounded in all the sutras, such as supreme truth and worldly truth, the three truths of non-substantiality, temporary existence, and the Middle Way, mudras and mantras, the principle of the unconditioned, the twelve great vows, and the forty-eight vows. To understand this is to understand the teachings." - What it Means to Slander the Law

"The Great Teacher Dengyō in The Outstanding Principles of the Lotus Sutra writes: “The Tendai Lotus school is superior to the other schools because of the sutra that it is founded on. Therefore, in declaring its superiority, it is not simply praising itself and disparaging others. I hope that gentlemen of wisdom will examine the matter of sutras and on that basis decide which school they will follow.”" - Errors of the True Word and Other Schools

"Finally, with regard to the statement by the Great Teacher Kōbō, who cites On the Mahayana Treatise as his proof, that [the Buddha of] the Lotus Sutra still belongs to “the region of darkness,” and that the Lotus Sutra is a doctrine of “childish theory.” Such an assertion is totally preposterous.

The work known as On the Mahayana Treatise was written by Bodhisattva Nāgārjuna, who was a follower of the Thus Come One Shakyamuni. Why would a work by the follower speak disparagingly of the Lotus Sutra, which the teacher declared to be the foremost among all the sutras expounded in the course of his preaching life, and call it a doctrine of “childish theory”?

Moreover, there is in fact no such passage to be found in On the Mahayana Treatise. The teachings set forth in this work deal with the specific teaching, a doctrine expounded in the provisional sutras. This teaching cannot compare with the perfect teaching or with the true teaching, both embodied in the Lotus Sutra. How, then, could such a work be used to disparage the Lotus Sutra?" On the Relative Superiority of True Word and Tendai Schools

"His wife is a believer in the Lotus Sutra and therefore, although he may not have thought that it is the true sutra, it seems unlikely that he himself was completely opposed to it. This is a cause for hope. On the other hand, he put his faith in the Nembutsu and the Nembutsu believers, who disparage the Lotus Sutra, and was probably a Nembutsu believer himself, so I have doubts as to what kind of existence awaits him in his next life.

It is like the case of those who take service in the palace of the ruler and labor diligently there. Some are rewarded by the ruler’s favor and some are not. But if any of them commits the slightest error, it is quite certain that that person will be punished. It is the same way with the Lotus Sutra. No matter how fervently a person may appear to put faith in it, if, knowingly or unknowingly, he has dealings with the enemies of the Lotus Sutra, he will undoubtedly end up in the hell of incessant suffering." - Condolences on a Deceased Husband

"This passage of commentary is describing the benefits gained by the fiftieth person who hears word of the Lotus Sutra passed on from one person to another. The Buddha, having weighed these benefits carefully, kindly explains for us that all the benefits gained by practicing the provisional teachings over numerous kalpas, or the benefits of a great sage, cannot compare to the benefits gained by even an ignorant person who for a moment hears of the Lotus Sutra, responds with joy, and thus forms a bond with it. As we see in the sutra itself, the latter benefits are a hundred, a thousand, ten thousand, a million times greater. The Great Teacher T’ien-t’ai in his commentary is making this fact perfectly clear through his analogies. The tree known as the nyagrodha in one day spreads out a hundred spans in all directions and towers on high, and the bird known as a kalavinka, even while a mere chick, has a voice superior to that of all other kinds of birds large or small.

The long time required in the practice of the provisional teachings is compared to the slow rate at which many kinds of plants and trees grow to maturity, while the swiftness with which one attains Buddhahood by practicing the Lotus Sutra is compared to the way in which the tree mentioned above spreads a hundred spans in a single day. And the sages great and small of the provisional teachings are being compared to the other types of birds, while the ordinary person who has barely begun practice of the Lotus Sutra is compared to the kalavinka, which, while still in the shell, has a voice superior to that of all other birds.

The Great Teacher Miao-lo in his commentary explains this further, stating: “Probably those who are mistaken in their understanding fail to realize how great is the benefit gained even by a beginner [in the practice of the Lotus Sutra]. They assume that benefit is reserved for those who are far advanced in practice and disparage beginners. Therefore, the sutra here demonstrates its power by revealing that though their practice is shallow, the benefit that results is profound indeed.”

Ignorant persons in the latter age admit that the principles of the Lotus Sutra are very profound, but assert that they are not suited to our inferior capacities. This passage of commentary is describing such persons, who, while paying great respect to the teachings of the sutra, underrate people’s capacity to understand them and hence turn away from the sutra.

Again, the Great Teacher Miao-lo laments the way in which the teachings of this sutra are rejected in this latter age of ours, stating: “The reason that people hear of this teaching of perfect and immediate enlightenment but fail to respect it is that in recent times there is much confusion and misunderstanding among those who practice the Mahayana doctrines. And the situation is even worse because in the Middle and Latter Days of the Law people have little feeling and little faith. Though the teaching of perfect and immediate enlightenment may overflow the storehouses and its scrolls more than fill the sutra boxes, people give it not a moment’s consideration but rather turn away with closed eyes. How painful it is to think of them, being born in vain, dying in vain!

“Some people may say, ‘If you simply listen to such teachings but do not carry them out in practice, what good can that bring?’ But they fail to understand the profound and eternally lasting benefits of the Lotus Sutra. The Sutra of the Heavenly Son Abiding Goodness states: ‘Manjushrī said to Shāriputra, “Those who hear the Law, speak slanderously of it, and fall into hell as a result, are still superior to those who offer alms to Buddhas as numerous as the sands of the Ganges. For although they fall into hell, when they emerge from hell, they will on the contrary be able to hear the Law again.”’ Manjushrī is here making a comparison between the slanderers of the Law and those who, while offering alms to the Buddhas, fail to listen to the Law. Those who, on hearing the Law, slander it, are still by doing so planting the seeds for enlightenment in the distant future. How much more so, therefore, is this true of those who, on hearing the Law, ponder it carefully and diligently put it into practice.”36

The Great Teacher Miao-lo also states: “Even a single phrase cherished deep in one’s heart will without fail help one reach the opposite shore. To ponder one phrase and practice it is to exercise navigation [in crossing the sea of the sufferings of birth and death]. Responding with joy, seeing and listening to the teachings, are one’s host and companions. Whether one accepts or rejects the teachings, they have entered one’s ear and one has thus established a bond with them. And then, though one may comply with them or go against them, in the end one will because of this bond be able to achieve liberation.” - The Meaning of the Sacred Teachings of the Buddha's Lifetime

"Some persons use the practice of reciting the name of Amida Buddha to mislead others and persuade them to abandon the Lotus Sutra, committing the error of turning their backs on what is superior and following what is inferior. Others propound the principles of the Zen school, calling them a special transmission “outside the sutras”　and claiming that the so-called Buddhist teachings are not the true Law, disparaging the teachings in this way and displaying an attitude of great arrogance. Still others advocate the doctrines of the Dharma Characteristics, Three Treatises, or Flower Garland schools and relegate the Lotus Sutra to an inferior position, or proclaim themselves adherents of the True Word, or Mahāvairochana, school, asserting that the Lotus Sutra embodies only the exoteric teachings of the Thus Come One Shakyamuni and cannot compare to the doctrines upheld by the True Word school.

In this way, some persons go astray in doctrinal matters of their own accord, others do so because of the teachers they rely upon. Some propound mistaken doctrines handed down from the founder of the school or its scholars and teachers, propagating them over the long years and claiming that these are the true doctrine. Others, possessed by evil spirits or by the heavenly devil, spread evil doctrines, believing them to be the correct teaching. Some, having become familiar with some petty doctrine of Hinayana, arrogantly claim that the doctrines practiced by Mahayana believers are in error, and in their eagerness to spread their little doctrine attempt to suppress or take over the mountain temples where great doctrines and secret doctrines are taught. Then there are those other fellows who, having become possessed by a devil called the devil of compassion, don their three robes, take up their one alms bowl, and practice the one teaching of Hinayana, with their little doctrine confronting the temples of Mount Hiei, which are the rafters and roof beam of the entire nation, and Mount Hiei’s leaders, who are paragons of wisdom, and because the doctrines taught by these leaders are at variance with their own, presuming to call them men of erroneous views and men of evil.

With evil opinions such as this, these men proceed to deceive the rulers of the nation, leading them woefully astray and causing them to lose faith in the correct teaching. Such men do nothing but bring about the destruction of the nation and the destruction of Buddhism. - The Differences between Hinayana and Mahayana

"Or again in volume eight of the Lotus Sutra we read: “If anyone sees a person who accepts and upholds this sutra and tries to expose the faults or evils of that person, whether what he speaks is true or not, he will in his present existence be afflicted with white leprosy. If anyone disparages or laughs at that person, then in existence after existence he will have teeth that are missing or spaced far apart, ugly lips, a flat nose, hands and feet that are gnarled or deformed, and eyes that are squinty. His body will have a foul odor, with evil sores that run pus and blood, p.199and he will suffer from water in the belly, shortness of breath, and other severe and malignant illnesses.” - Explaining the Causation of the Ten Worlds