I'm not sure it's possible to police anything fairly. But most internet snark is dreck and has a degrading effect, so we do what we can. Were it to take over HN, nobody interesting would stay here anyway.

It's a mistake to compare other contexts, such as writers or scientists sparring amongst themselves, to an internet forum. A large internet forum is a mile wide, an inch deep, and never far from a swamp. It has its own odd dynamic and needs to be managed accordingly.