These guys are never able to cite examples. Every time the conversation comes up, they fly in with a vague innuendo, "oh, you know those topics--I'm not going to say it!" plus a "trust me bro" and then fly off without actually getting specific.

HN has at least several almost occasionally "active" shadowbanned accounts that like to literally call for jews to be gassed.

I'd call that controversial.

If you don't have showdead on, you should.

https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...

you'd have to do additional analysis to find which accounts stopped posting after the linked warnings though. It's not usually the opinion itself that's the problem, but that users with controversial opinions have other things going on, so the controversial opinion is often delivered in a “wake up sheeple” flamebait persecution complex “in smart and everyone here is an idiot” style, which isn’t conducive to constructive debate.