I mean, surely we can agree that in the kind of sentence we are talking about here, using "figuratively" instead would be utterly idiotic. Nobody would ever say "He is figuratively the creepiest dude in the universe" (except perhaps to prove a point in this discussion). You either put "literally" or you put nothing at all. So using "literally" there isn't a grammar issue, nor is it a vocabulary issue. It's an exaggeration issue - part of a rather widespread tendency in popular speech to use extreme hyperbole to humorous or emphatic effect. I don't see why that word is singled out any more than the million other ways of doing that (no, that actually wasn't intentional until I read it again and noticed).