Gravity certainly doesn't require absence of evidence for a positive assertion.Nope, not avoiding it at all. If you take every wording perfectly serious (and I congratulate you for that) I rephrase my statement: atheism is the logical conclusion as it is most likely the truth. Just like gravity for example. The only thing we really do KNOW is that there is not nothingness. Everything else is certainly a matter of probability.
Atheism is only logical in lieu of certain values being held as true ... none of which have anything to do with having a monopoly on rationalism.