I think many of the posters, expressing anti-christian sentiments, are feeling judged, and that's the key. I'm sure that most do not lump all Christians together.
When someone tells you that you are vile, evil, a murderer, and then quotes the Bible, don't you think that would cause someone to lash out?
There is nothing wrong with someone telling their version of the truth, but after all, this is a debate forum. One person's truth is not another's, obviously.
I think there is a great degree of "judging" from both sides, really.