This is your opinion. There are other possibilities.
They are unprovable but irrefutable delusions or part of frameworks people made up to come to peace with the truth.
Examples frameworks would be pitiful reasons to exist like "keep the species alive", "keep the family line going", "I need to be behave this and that way because my deity will judge me when I die" etc.
Regardless, this (particularly, the conceptualization of the supernatural) is somewhat of a variation of the kind of thinking that I'm referring to. I don't disagree that this isn't formally documented in scripture, but nonetheless it seems to have somehow ended up broadly installed in minds (both theist and atheist, to be fair), not unlike how various behaviors can be observed in theists despite it not being a part of formal scripture.
In reality atheists don't have anything in common with one another. There is no shared belief system or a set of scriptures for atheists. Stalin and Mao did however have a shared belief system and it wasn't atheism.
This seems unlikely.
> There is no shared belief system or a set of scriptures for atheists.
Large quantities of those I talk to on the internet seem to disagree.