He's here to push Catholicism and all it's heresy. I personally don't have a lot of time to deal with all that. We have to have some doctrinal standards and draw the line somewhere. Catholics, Muslims, Hindus, homosexuals, etc. are welcome if they're interested in the Bible/Christianity and they're not here to promote heresy.
Also please understand that, with thousands of people using this site, bans will happen regularly. If we didn't ban, Christian Chat would not be Christian chat. And we won't be able to explain all bans to everyone.