People hardly "vehemently hate on it" any more. Nor is it an actual case of denial. It's just...ignoring it. Most people who frequent NMA nowadays have never actually played that game, nor ever will. It isn't referenced in any of the later titles, it's considered non-canon by every source out there, so people just stopped caring a long time ago. Those who did hate that game with passion, well, they too simply started to ignore it a long time ago.
It's not a denial as if FOBOS doesn't exist. It does, people know it. But it's existence is pretty much irrelevant, and it's mostly forgotten, nothing but a random piece of trash.