Since non-believers in the supernatural almost never initiate discussion, but only respond to the claims of believers, there would be no point in a separate, ring-fenced forum for them. I understand that it would be more cosy for the believers if they could all agree with one-another in their own forum, and not be expected to actually think about the matter, but that would be yet another kind of religious privilege, wouldn't it?
You all have the right to believe whatever you will, and I respect that right. But I have the right not to believe it, and not to respect the actual belief.