:SGK is technically classified as a "new religion" under the umbrella of Buddhismsee the post on this page of entries in other encyclopedias.
The fact that it is "new", whereas Nichirenshu is traditional, with more than a thousand years of tradition is a substantial issue in light of traditional Buddhist organiation/ordination practices and those of SGK, which portrays itself as a lay Buddhist organization when it is actually more of a "new religion" with Buddhist origins, but a completely different organizational infrastructure, and different methodology for transmitting teachings.
There doesn't seem to be anything comparable to the historical circumstances of any article on other religions, but you haven't specified any. 連絡 見学/迷惑