Some people believe in homosexuality because they believe it is genetic, and people are born that way. I don't feel the same way, I think homosexuality is ultimately a choice that we make, and just as 7891b says it is a sin just like any other sin.
I think it was more of a reference to paganism.. but I could be wrong. I've read that Halloween can be a dangerous holiday spiritually for Christians.
My girlfriend thinks that Halloween is just fine to celebrate, however.. and she's a Christian too.
I have a gay friend that has stopped leading the gay lifestyle for fear of punishment on judgment day. I think it's incredibly honorable to obey God the way he does, despite his physical attraction to other men.