Why do Athiests require 'proof' that God exists?

[Epimethean]

It was so-called neo Platonists such as Augustine and Aquinas who tried to insist that truth can be revealed by reason alone.

Reason informs observation. An informed eye is often able to discern relationships that go unnoticed by the untrained. While the demand for evidence is laudable, one must also be prepared to recognize and receive it as well.

And a lunatic is able to see and hear the giant talking rabbit in Uncle George's La-Z Boy. So, unreason also informs observation. In the case of gods, there is no reason to believe.