>>5
I agree with you, but I also believe that /b/'s hatred of pedophilia is much deeper than a sense of self-preservation. Young self-hating westerners hate two things very strongly: pedophilia and racism. While there's legitimate reasons to be opposed to these things, /b/tards have an irrational, visceral hatred that goes far beyond reason.
As #4 said, these are exaggerated feelings. Perhaps these two things are selected because they are the easiest targets (as regarded by our culture), and the person's subconscious is desperate to find something they can regard as lower than themselves (not that they actually are low, but that their self image sees themselves as being so).
This defense mechanism falters, though, and /b/tards will of course turn on themselves. Since it's an anonymous board, it's easy for the mind to believe that it is attacking someone else when on a different level the person is actually attacking himself (or perhaps the other way around in some instances).