"Onager,
If belief in God were creating good citizens, everyone would have accepted God even if he were not real. Everyone accepted electricity without even labeling it American electricity, UK electricity, Russian electricity …etc. because electricity is good.
If belief in God were not creating good citizens, some would doubt the existence of God which means atheism would only appear after decay of theism.
4 hours ago venus"
Venus,
Er, You know that the UK has different electricity to the USA don't you?
The gods are humans attempts at explaining the world around us. At the moment that one person ascribed a supernatural cause to a natural phenomenon and someone else didn't believe him, atheism was born.
David_Jay says that the state of everyone before this was also atheism but I think it is something purer than that. Proto-atheism maybe. What is it called if you don't have a belief in gods but you also don't even have a concept of gods to not have a belief in?
For example read this sentence:
There is an alien race called the Boqtic. They are like insects in appearance and are very good mechanics.
Now, having read that sentence you (I hope!) do not believe that the Boqtic exist. You are Aboqticist.
But what was your belief before you read that sentence.?