Let's see if I understand this. It may be bad to call people fools (or maybe not). Well not fool actually, but whatever Aramaic word he happened to have used. However, since Jesus didn't specifically condemn the use of the words moron, idiot, asshole, or any other insult you can think of, then it's okay to do that, even if it's a synonym for fool.

This is a strange morality that Christians have.
If God wanted us to be Atheists we'd be born that way.