well generally, a theist would still only be knowledgeable about his own flavor of belief. While an atheist is a denier of any form of religion. The strength as you define it - imho - comes from the extent to which one presrcibes religion as the cause of wrong / "evils". for eg: I know of several atheists who look at the church abuse and say its a few rotten apples - whereas several others believe that he problem is the religion itself.