Snark, I think, correlates positively with terseness, and terseness correlates positively with upvotes - it's much easier for someone to read a short comment an

Snark, I think, correlates positively with terseness, and terseness correlates positively with upvotes - it's much easier for someone to read a short comment and say "Yes, that's it" than a very long one. So there's both a prevalence of those comments higher on articles and an effective pressure to make those comments. (There are other things that correlate positively with terseness, like outright insults, but also strongly correlate negatively with upvotes. Or there are things like pun threads, which are popular on Reddit etc. but are just culturally unpopular here, for some reason.)