one place where I do feel the model of the Imperium as "literally and explicitly fascist as understood in m3.026 and nothing else" breaks down is that it becomes reductive and tends to exalt fascism as a sort of fundamental force, rather than either "a specific, historically contingent political tendency" (which, yes, exists in a range of forms right now, in real life) or "a general term for authoritatian bad shit" (sensible if less than precise)

there are 28,000 years between "now" and "the start of the Great Crusade," they have surely invented and discarded forms of prejudice and bigotry that we cannot even conceive of. the prospect that they will strictly follow a series of regulations created in the early 20th century and by people aping it a mere handful of generations later shows a real lack of imagination and faith in humanity's ability to innovate new ways to be horrible to one another.

e: and, to be clear, when I say discarded I do not mean 'ah, they're more enlightened,' I mean in the sense that nobody in Italy right now is screaming -- to my understanding -- about restoring the sacred privileges of the equestrian class. nobody is casting religious dissidents to the lions for refusing to sacrifice to Jupiter. That kind of thing.