Why atheism is irrational

[Gilgamesh]

Ryantology: Ooh, good point! Rational response #3! It doesn't prove atheism is itself rational, you're right. But I think it shows that for the vast majority of atheists, their atheism is irrational.

It doesn't. It shows that they're irrational about whatever they're irrational about. Their lack of belief in an unsupported claim doesn't become any less rational on the basis that they hold irrationalities on other topics.