Except religious beliefs don't have precedence over every other right.  You can't kill someone and claim you did it as part of your religion, so that you're protected against prosecution.  Freedom of religion doesn't allow you to break the law in the name of religion.  Discrimination based on religious beliefs is still discrimination and is still illegal.  If you had any sense, you'd know that was true, just based on the fact that this baker isn't trying to use religious freedom as a defense, but instead first amendment free speech as an "artist".