"Oh, so God loves us. That means He wants us to be happy. Being gay makes them happy, so they should be allowed to be who they are and even get married b/c that makes them happy. What do you mean 'God doesn't allow that'? Why do you hate gay people so much? God loves us, why can't you just love?"
You can't win with these people.
But they don't have a sense of what Natural Law is or a sense that God is Justice itself. So there's a lot of work to be done.