Like the laws of gravitation, these principles hold true regardless of one's religious views. This is where the aspect of the public forum comes to play. They may believe what they want in the privacy of their own minds. They may even try to convince others to agree with them. But once they make this attempt at persuasion, their arguments become subject to the scrutiny of others.
Beliefs are sacred only to the extent that they remain private.
When theists approach me with their various god claims in an attempt to convince me to give assent to those claims, I respond exactly as you have described. This includes when a theist stumps for a certain public policy based solely upon an argument exclusive to one's religious tenets. Christian homophobes almost always try to bring other angles into play, such as alleged psychological damage, when arguing against homosexual rights. They do this precisely because they know that we all know that the purely religious angle is utterly without foundation in a public discussion. In the sense that any hobby might be seen as time-wasting, I might agree.