We are, after all, humans. Not machines. Our goal may be to remain civilized, yet we sometimes succumb to our raw emotions. Hackers are a weird bunch (I know, because I am one). We see ourselves as logical, prudent, and fact based. In reality, we are as emotion led as any other individual. Biggest difference is that we work with machines. A machine cannot (yet) get angry or offended. And when the day they are able to do so, I will no longer will be able to write code without being sued by the computer I'm programming. Alas, I'm not defending any behaviour. Just stating something we forget. Hackers are people. People are irrational. We are just a bit more logical than other professions, but not less rowdy. Though losing our shit is sometimes the right course of action. :)
Granted that people can be emotional, but the aggregate tone of HN itself isn't completely stable, which it would be if it were entirely determined by generic facts about people.