This is interesting because the least toxic places on Reddit are highly moderated (askscience, and askhistorians are the two biggest examples). Indeed, Hacker News is just essentially a highly moderated subreddit, which is its attraction.
HN it may have pretentious articles, the comments are the most substantial. Lately I've been lurking through HN Classics (1) (Many research papers and pdfs posted on HN that are old) and the comments are the best part of them.
