It is very hard to feel peaceful and at ease when one is at cross purposes with oneself or the teachings one embraces are in conflict with each other. SGI says that you, the members, are all Buddhas but there is no autonomy in the SGI. There are constraints. You can't go preaching Buddha Dharma as you see fit in their District meetings. More importantly you can not choose a copy of a Nichiren inscribed Gohonzon. How can a "Buddha of Absolute Freedom" have constraints? When one is told one thing but every member acts contrary to what is taught, it is impossible to develop doubt free faith in the Lotus Sutra, the only means in the Latter Day to obtain Buddhahood.
Then, there is the matter of the teachings [doctrines] expounded by Ikeda and the leaders which don't match the teachings of the Lotus Sutra and those expounded by Nichiren Daishonin. A thoughtful or studious person will know something is a amiss but when he questions his leaders, he is told that the SGI teachings are not amiss, "you are amiss" [lack faith]. There is a conflict between what you are reading, seeing, and experiencing and what you are being told. Again, in such a situation, it is impossible to be at peace or to develop doubt free faith, the prerequisite for attaining Buddhahood.
Though the Lotus Sutra promises, "peace and security in this life and a fortunate birth in the next", in the SGI, one can not be truly peaceful because SGI's faith and practice is not the faith and practice of the Lotus Sutra. They would counter that if one practices the Lotus Sutra correctly, one will encounter the Three Obstacles and Four Devils. I would respond, "encountering the Three Obstacles and Four Devils is not an artificial construct like cleaning Sensei's toilets." One who practices the Lotus Sutra correctly is peaceful even while encountering the Three Obstacles and Four Devils.