Is atheism a belief?

[Belacqua]

I understand what's being said....today, and reject it, today, from my perch as a gnostic atheist.  

Good. That's all I was talking about. My claim was about adult atheists, so baby atheists aren't included. 

You hold it to be true (i.e. you believe) that the Christian claim I quoted is not true. If you held that it were persuasive, and true, you would no longer be an atheist. 

Therefore, your atheism as currently constituted is based on at least one belief.