This is my issue with this argument - seeing or interacting with or selling goods or services to a gay couple does not in any way shape or form force you to violate your religious beliefs. You can only do that through your actions. Those are just convenient excuses to discriminate against folks that you don't like or don't approve of. And if you want to make that argument then you would also have to include murderers, liars, thieves, adulterers, etc. because those sins are just as bad. Do you refuse to serve divorced people?