HN is not "the internet". I don't think HN should strive to be as terrible as most of the internet can be. If I want "the Internet" I can go to /r/all. That is a much better snapshot of what "the Internet" actually is. I don't see why it's a bad thing to want HN to be better than most parts of the Internet.
I also think your type of attitude really brings communities down. People who treat others with disrespect and insults like to defend their actions as "This is the internet. Deal with it." I've never thought it to be a particular worthwhile argument.
Surely there's a some balance point between "hugbox" and "hatefest". Also, we're not talking about the Internet, but a small self-selected community of humans that happens to connect via the internet.
For many things (especially raw information), I appreciate that cynicism. For launches and discussions around early products, it annoys me to no end. I think it really shows the character of a person who, when somebody puts themself out there, their first reaction is to tear them down.
Alas, there is probably nothing that can be done. It is the tragedy of the commons, where goodwill is the resource being depleted.