People are more passionate and the internet anonymity brings discussion further and harder than it would be face to face, but that doesn't make you anti-social to defend things more black-white.
When you discuss someone IRL you will also consider his feelings more and you will look him in the face and see you can't go any further. Different media, harder to tell the other players real feelings.
But as some topics are fought between 2 or more camps in a very hostile way and to the bone, we also see other topics get recognition for the others point of view, yet disagreement. The internet is filled with more extremes than the real world, but at the same time, as long as you know you are on the net, you know what to expect and you know that that person isn't attacking you, but your ideas.