[Danny]

I know why Christianity was anti-Homosexual, but I don't know about other religions. Come to think of it, I can't think of any other religions that are that Homophobic, really - what other ones are there?

Christianity declared itself Homophobic in order to oppose the Romans, as Homosexuality was (rightly) considered normal by the Romans. That's all. Homophobia was simply a political move to ensure that Christianity's supporters were thoroughly anti-Roman... That's why they made up all that shit about it being "immoral", "unnatural", etc. Then when they wrote the Bible, they put little hints of it in there, so that it became Official. Over the years, it became so much a part of Christian Doctrine that even after the Roman Empire became Christian, the rules against Homosexuality remained...