If you are offended that people believe in Christianity, that's your problem. People have the right to believe in what they believe. Just as the forums agnostics, atheists, Buddhists, Jews and Hindus have the right to believe what they like, so do the forum's Christians.
This is meant to be a discussion. No one has the right to tell any one else they're wrong for believing what they believe. No one has the right to make fun of someone's beliefs. No one has the right to attack any other forum user personally.