I dont think the choice is between "warm and fuzzy" drivel, and snarling flame wars. I like to think of it as an online version of the late night college dorm debates, over a pizza and a game of risk.
People can have strong opinions, share them, and debate without delivering the verbal equivalent of bodily harm.
Imagine you were invited over to a party at a friend of a friend's. If the guy were laid back, you could talk about anything - but you wouldnt let it get personally insulting unless you were intent on being a jerk. The concept isnt hard.