See, for any given philosophy or social movement with any significant number of followers, there’s a core of reasonable, intelligent and calm people. These are the liberals who think government is the best way to help people, the conservatives who think that the most effective government is a small one, the tolerantly religious and the atheists who respect religions despite their lack thereof.
However, the loudest and most vocal of any particular group are also the dumbest and most hateful. These are the conservatives who think liberalism is a genuine mental disorder, the liberals who think all conservatives are racist, the zealous religious morons who scream about how every other religion is wrong and evil, the atheist who says churches should be burned down with their worshippers inside. And since they’re louder and more eager to speak, you have to get through those to get to the reasonable ones.
So the end result is that each philosophy or movement sees its own side as a largely reasonable group with a few bad apples, whereas every force in opposition to them is full of blind, stubborn morons.
That’s my theory on it, anyway. Thoughts?