That’s really not true. That’s the Flewsian definition of “atheism”. There are atheists who disapprove of that definition, atheists who argue that there is no God. There are several definitions of “atheist” in the literature and historically it means the belief that God does not exist.
I know, but some do claim they have never seen evidence for God yet at the same time admit they have no idea what would characterize such evidence (one person however did - admirably - say what would characterize it).
How can one argue that it is logical to say “I cannot see any examples of X and I do not know what X looks like”?
We need no alternatives so why would you expect me to provide alternatives? It is logic and reason that leads to the view God exists because there are questions about the natural world that cannot be answered by recourse to that natural world, they can only be answered by postulating something not naturalistic.