If we're talking about having gay sex, as I don't think you're referring to the sin of wearing mixed fibres, nor do I believe that you are concerned about the sin of working on the sabbath or the grievous crime of breeding two different breeds of cattle.How do you atheists manage to remain so oblivious to the harm of sin???? Or is it your own perverse mind that perceives iniquity as righteousness?
If we're talking about men lying with men, and so on. Then we manage so well, because people like myself and many other personal liberty loving people, do not consider homosexual relationships and all that entails, as sinful.
I've dated other guys. I've had crushes on other guys since I was at school. Nothing sinful or evil about that. Just natural inclination. I like girls too. Probably more, because I get on better with women, basically.
I don't worry about it, although I can imagine if you think sex in general is filthy or dirty, you might.