Fuju Fuse concerns temples and such, not individuals. It has to do with the fact that there are other Buddhist temples that take money from the government, Myanmar comes to mind, and because they take money from the state it compromises them.
My concern is that the whole concept has been mis-interpreted to the point where you must be a member of a sect, not one of the devilish ones of course, to be able to donate. It's just ludicrous.
Your explanation of the rational being to avoid chance compromise sounds good. But if the articles are a valid presentation of the true beliefs then its hard to reconcile your statement being the true intention.
(1) Truth in Buddhism is not determined by human judgment but by the Buddha's words alone, as recorded in the ultimately true scriptures;
(2) the Buddha Sakyamuni has a profound link to our world, while Amida, the Buddha of the Pure Land sects, does not;
(3) There are provisional and ultimate teachings within Buddhism;
(4) The Lotus sect was established not by a human teacher but by the Buddha himself;
(5) The teachings of the Lotus sect are transmittedin a double fashion, the essential transmission a direct one from Sakyamuni based on the Lotus Sutra, and an indirect, intellectual transmission based on the writings of the patriarchs of the Tendai sect;
(6) The Lotus sect is superior to all others; and
(7) The Lotus sect may not have any association with slanderers of the Dharma
Items 6 and 7 clearly imply that outsiders [institutional or individual] are to be shunned even if that was not what was meant in the author's heart-of-hearts. It would be a different story had it been stated as you did.
But there is in the list clear disregard for reality and twisting of Buddhist principals such that it calls into question the heart that produced the manifesto.
Among other things, sects are aggregations of people who have various levels of understanding. As such, and with respect to the Buddhist ultimate, can any be said superior in so far as any of the membership is inferior to any aggregation of 1-N elsewhere who are more adept in the ultimate.
If we take Buddha for being the most 'adept' then according to this doctrine all of Lotus sect adherents are fully awake. Which would be easily and observably proven false for the bulk of professed adherents were they held to the standard of item 1.
And, those who are ignorant of Dharma [or lazy in approach to Dharma even when they know better], regardless of the label under which they claim to stand, cannot be other than slanderers of Dharma. Item 7 at face value therefor disavows association with its own.
Whether referring to only temples or not, as its presented "It's just ludicrous."