No one is 'forcing" this bigoted baker to do anything. He can be hateful towards gays, jews, blacks and women all he likes in his personal life. He can believe anything he wants about groups the disagrees even though it's highly irrational.
But what when he avails himself to the public marketplace he should either abide by the proscribed rules or quit. There is nothing that says baking cakes is practicing religion and nothing about the law that he violated that requires him to believe anything.

I think something that isn't explored is that 99% of those who claim this religions exemption only target one group - homosexuals. They never target adultery or other sins that the bible talks about. This to me shows that it's not really about religion at all.