A couple of corrections. Agnosticism isn't the belief that god might or might not exist and you have yet to figure it out, it is the position that it is fundementally impossible to know if there is a god or not. Atheism is the position that it is possible to know if there is a god, and there is no evidence pointing to the existence of one. Theism is the belief that we can know there is a god, and we do know because he interacts with his creation. Deism is the belief that we can know there is a god, there is evidence that he exists, but he does not intervene with nature.
As such, an atheist doesn't argue with arguments for god because of fear of change, but rather because of the desire to be accurate. If somebody says "The sun rotates around the earth" my correcting the person would not be a result of my being afraid to accept change, but rather upholding the logical positivism that demonstrates to the contrary.
Also atheism is not a positive conclusion, rather it is a nuetral stance (Unlike agnosticism which is a positive conclusion, namely that it is impossible to know whether or not any gods exist). I do not believe in leprechauns but it is not because of my exhaustive research on leprechauns, it is because there has been no compelling evidence to suggest that leprechauns exist. As such the atheist position is not "God does not exist" it is "There is no compelling evidence to suggest that gods exist". A subtle but important difference.