Another possibility, but not a likely one, is that the site has been hacked by someone that is trying to make them look as bad as possible.

Unless this hacker was able to get the COO's HN account as well that seems unlikely. And even then a call to someone at YC to jump into the thread and let everyone know it was a hack wouldn't be too hard.

Yeah, their CEO. cymbal

Bit frustrating that you see poor behaviour that's hard to understand and leap to "mentally ill", rather than "scumbag".

That's just trying desperately to give the benefit of the doubt. "Surely no one would be this bad on purpose."

As austenallred mentioned, I'm trying to give them the benefit of the doubt.

But by linking mental illness to scumbag behaviour you're making life worse for all the people with mental illness who aren't scumbags - which is most of them.

A group that I am a member of. Perhaps I'm biased but I don't feel like my life is particularly worsened.

I've had the misfortune of bearing witness to paranoia fueled by both mental illness and drug abuse (and a combination of both). I've also worked with and for unapologetic assholes. There are things about this case and his communications that have me leaning toward the former.