That was kinda my point.
If pushed hard enough, any atheist has to, by definition, be an agnostic, simply because you can't know how the very fabric of existence came to be. It is simply out of our level of understanding.
I'm an atheist in so much as I don't believe there is a dude with a white beard and hippie son who gives a solitary shit specifically about our little corner of the cosmos and its inhabitants, but I cannot say with confidence that there wasn't some kind of, what we would describe as 'sentience' behind the creation of all things. I personally don't think it seems all that likely and there is certainly no evidence to suggest there is, but we have no way of ever knowing for certain. Hence, agnostic.