That's an interesting thought, for sure. I should point out that this doesn't only apply to facebook, but other large discussion forums as well: reddit, 4chan, tumblr, twitter etc.
> some hidden human need/instinct to argue with people who they believe are incorrect
I've said it before, I'll probably say it again: this place is chock full of people just itching to tell you you're wrong and why. Don't get me wrong: obviously there's also a hell of a lot of great discussion and insightful technical knowhow being shared by real experts — but in my experience I also do have to wade through quite a lot of what feels like knee-jerk pedantry and point-scoring.
When I'm wrong I want it explained to me why. Even when I'm right about something controversial, I want to see the best arguments to the contrary.
I don't want people to be less argumentative. I just want a higher intellectual caliber than what's generally available on facebook or twitter, and HN fits the bill reasonably well.
When people here tell you that you're wrong, they tend to do it with style.
One time I made a comment about how dividends affect stock price and someone spent like 2 hours writing a program in R to do some analysis just to prove me wrong.
