Atheism is a belief system accepted on faith - a religion, in other words. Neither Isaac Asimov nor Gordon Stein - two great twentieth-century atheists - claimed they could disprove God's existence. By failing to do so they admit their worldview is held by faith, just as every other worldview.
I agree that atheism should be treated as a belief system or, basically, as a 'religion', even without a deity. There are atheists who quietly go about their lives without fervor, and then there are atheists (like many in the ACLU) who have made it their lives' prime directive to face down and defeat other belief systems who have deities. Those 'fundamentalist atheists' most definitely should be treated like a religion, and be kept out of national policy as with any other religion which mandates conformity for all.
One can accept anything without evidence or proof simply because one wants to. Believing or accepting something on faith does not a religion make.
Atheism, strictly speaking, is not a religion regardless of the "faith" it requires. But... I clearly understand why it could be deemed a religion and indeed some of its cousins are religions... humanism, anti-theism, etc... -jw