I’m not even sure they’re a bot, I’ve seen low effort trolls pop up all over the site now, usually quickly killed off.

The most curious case, was an [banned] account making comments like this with a 10 year tenure. I’m not sure if they were posting unhinged crap for 10 years, or if they at some point were relatively benign until losing it for some reason.

or the account owner isn't the person posting. HN doesn't have a captcha for login attempts and there are probably lots of shared user/pass combos (or just easy to guess passes).