No it isn't, I am not semantic, and I don't take orders.
So then, I guess we can only ask which Traitor Legion are you part of? :P
The Warp/Immaterium is psychic reflection of material universe, and as such neither is it primordial, because material universe predates it and not the other way around
But to those who are of the opinion life is hell on (Earth) Holy Terra - a heretical thought, I know - would The Warp not be just hell on/in no place in particular?
neither is it evil, since it merely reflects psyches of the mortals
And you think most mortals in the Warhammer 40K universe are... not evil? She Who Thirsts did not exactly come out of good vibes, you know.
Aren't all (or at least most) demons fallen angels? I remember Crowley is called a demon all the time Good Omens.
In the traditional sense, yes. But in some (non-abrahamic) cultures their equivalents are distinct and complementary antagonists of good, not something corrupted or fallen from grace.
What comic book artists and game designers come up with nowadays is pretty tame in comparison. I don't know who first invented the "organic/flesh hell" imagery - it's pretty cool though.
A pitch black and frozen hell would be far less picturesque :P. Yet not less effective. Imagine freezing "to death", yet never dying, in pitch black, for all eternity. One might even dare say the origins of a fiery hell lie in the geographical region inhabited by the people that imagined it. I would not encourage such heresy, of course.