I think it is fine to criticize certain aspects of person's religion if you believe that those aspects are interfering with your life or denying you certain liberties. But I think making fun of the basic tenets of a belief seems kind of immature to me, like taking a religious symbol and making a cartoon out of it, or taking a quote out of a religious book and making fun of how crazy it sounds. We wouldnt make fun of a person's culture, would we, even if we thought that certain aspects of the culture are sexist or mysogenistic? Likewise, I dont go up to a Christian or Buddhist and say "your religion is a joke". For one thing, I've realized that no matter how hard you try to convince someone their belief system is illogical, outdated, etc, they usually wont become an atheist. And because they're happy the way the are, what good would it do?