I’m a Christian. I go to church, I lead a Bible Study once a week, and I believe in the Bible and what it says. Consequently, I believe that homosexual sex is sinful.
While we’re on the topic, I also believe the following things are sinful: gossip, deceitfulness, hatred, and prejudice.
But you notice something about all the sins in the above paragraph. Every single one of them is 100 per cent legal.