This is a lie. If every atheist really believes that he doesn't really know, they wouldn't be actively trying to convince others to believe that there is no God. Atheists only admit that they "don't really know" when they engage in a real debate. When most atheists talk they talk about how ignorant it is to think that God exists, and how there is
no such thing as God, which most of the time reflects the ignorance of most atheists about atheism itself..
And if you need an "evidence", just check the meaning of the word atheism in the dictionary..
- a·the·ism
/ˈāTHēˌizəm/
Noun
The theory or belief that God does not exist.
So stop kidding yourself. Atheists don't believe in that, and they don't admit it, except when they engage in a real debate that forces them to admit it.
And by the way, there are logical reasons that make me believe that multiple Gods and materialistic Gods can't exist. If there was to be a God, then he has to be only one (meaning going in one direction, rather than the mathematical "one" we use to count things) and he can't belong to our universe and can't follow its laws.
"Metaphors" is not something religious people invented. It's something 1- mentioned in the Quran for example many times, that God gives examples to people hoping they could understand, 2- it's something common we use everyday in our life.
Different people will interpret religious book in different ways to suit what they want. Hell you see people differ in their interpretations for human-written constitutions, how on Earth would you expect them all to agree on one interpretation for books talking about things we don't know much about (especially when you only focus on the parts that we don't know much about).. There is a difference between religious people and religion, something you don't seem to be able to grasp.