I don't think you see the whole of the harm done here. Yes, the extreme opinions come from one side, but to deal with it, the non-extremists have to take opinion-suppressing measures. Just the process of recognising and flagging posts that are bad for us is polarising.

There's a balance to be struck: I don't like the idea that the extremists determine what interesting content is permissible to discuss on HN. But while bringing attention to and discussing this article is good for consciousness-raising, I think this polarising process is damaging HN.

Which reminds you that HN moderation got outsourced to affiliates of the Democratic Party