Nic. Generally I would agree with your definition if it was culturally relevant but it's not for those here. For those growing up where belief or ideas about deities is rare, sure then the person may never have even thought of a creator or deity in which case their being "without god" would simply be a natural state of being rather than a system of belief or even agnostic.
A lack of belief is not the same as belief of lack. atheist != agnostic.
Your getting upset about what you Believe is a false claim is a good piece of evidence.
Reading your first post on the old thread, I will disagree with your definition for reasons stated above as well as empirical evidence that by and large those identifying as atheists hold the positive belief that god does not exist rather than not holding a positive belief that god exists. And many of those atheists are quite vocal about their positive belief and how stupid religious people are.
Disagree? Tell it to the self proclaimed atheists who give your non positive belief holding self a bad rap then.
I have no stake in it and am emotionally detached from the issue so I'm just calling it as I see it.
Incidentally, there are quite a few good comments in that thread that indicate that your hardline definitions are too restrictive and force people to choose a side that really is not relevant for them nor reflective of their views. I recommend going back and reading them again.