I'd say that even though upvotes and downvotes are somewhat helpful it is the mentality that differentiates HN from other communities most significantly. We can't outsmart human stupidity with technology.

Sure, we have loads of people who want to game HN to push their own agendas but at its core HN users actually welcome new points of view.

There is nothing wrong wrong with, say, fighting for animal rights. But the moment you consider yourself an animal rights activist you're very likely to give up common sense and the ability to value any input that doesn't conform with your peers' opinion. Basically you become a one-dimensional character.

Pleas note I used the word "likely." I am not ruling out that there are open-minded animal rights activists!