He is definitely Hellbanned. He made a poor-taste attempt at humor on a mental health post (https://news.ycombinator.com/item?id=407576) which was voted to oblivion, and every post since then is [dead]. Looks like it took him a few months to find it (I had to go back like 10 "more" clicks to get to his non-dead posts).
So HN can be more like every other internet forum since Usenet in 1985 and angry repressed basement dwellers can unleash their fury anonymously to make up for the fact that they can barely look other human beings in the face?
Plenty of places to do that on the internet, I'm happy for one place enforce a higher standard.
