Another faulty claim about atheism is calling it an ideology, a doctrine or belief. I've had discussions with theists that were stuck on this claim, none of my arguments proving the difference of atheism and ideologies penetrated their conviction (since my last debate on this issue I thought of a new way to prove the point, let's see if that one works). I don't understand why this claim seems to be so important to quite a lot of theists - seriously, I have no clue. The first time I encountered that claim I thought it was just a minor misunderstanding of what either atheism is or the word ideology means. I then had to realize that it apparently wasn't.

Assuming that I'm not the only one who has heard that particular theist talking point, I'd like to hear your points of view about this. Why is this claim of so high importance to many theists that they will repeat it no matter what?

Can it be that theists that actually secretly feel doubts somehow find it more valid to reject atheism when they can call it an ideology? And if so: Why's that? Any answers or theories on this one?