That's why atheism is not a "rejection" of God, but a lack of belief.

It's very easy to lack belief in every possible conception of God, including ones you've never heard of. Just like it's possible for you to have lacked belief in the red-and-blue striped monkeys that live in our asteroid belt and offer the power of invisibility to anyone who worships them by burning cauliflower as a sacrifice...even though you've never heard of them until just now.