Actually, seeing that you have a recent membership (4 days ago) according to your profile, how would you know the popular trends of anyone here (much less what the beliefs are of any groups)?
Furthermore, as a long time member, I don't believe that is true. You might have a skewed perception as your focus may be on that issue and you've found some debate on the subject. Perhaps some members on A2K who follow atheistic views are more vocal than others? The subject of atheism on many forums/fora seems to be a point of lively debate.
Furthermore, as for my personal views as a non-religionist (probably an agnostic), I can find the logic of atheism far more defendable or logical than Theism or religiosity. Although as a point of logic, I do not see the opposite of religion to be atheism. I would call it secularism or non-religionism.