Correct, and what you said I'll disagree with since atheism is a rejection of the claim of theism and does not require the making of the claim "God does not exist." and because, under your definition, any singular statement of belief has a passing resemblance to religion.  This ignores the definition of religion.

In the gumball example I'm not stating that you're wrong, I'm failing to accept your claim.  That does not mean that I have accepted the counter claim that the opposite is true.  I could still reject the opposite claim.

A Google search brings up a definition consistent with what I'm saying - A disbelief or lack of belief in the existence of God or gods.  Disbelief being a refusal or inability to accept something as true.  It is the failure to accept, not the acceptance of the counterclaim.

And a quick Google search also confirms that agnosticism is about knowledge as it relates to God.  Not Gods existence.

By definition I am an agnostic-atheist.

Merry Christmas!