@fresco,
Society has a basic need to control its members. This is not a cognitive urge, control is a fundamental basis of any society. Without the ability to ensure its members accept basic ideas of right and wrong and identity and follow basic standards of conduct, the society will be unable to function or to meet its basic needs.
You are trying to make a distinction between a "believer" who believes there is a God and an "Atheist" who believes there is no God. The word you keep using is "rationality".
Unfortunately, "rationality" doesn't help your case at all. The fact is that any human society is necessarily based on things that are accepted without proof. There is no objective rationality to values, or identity.
Take the idea that "all people are equal". This is a key value of most modern Western societies. It is the foundation to sacred ideas like human rights. Yet, there is no proof that "all people are equal". Not all societies have accepted this, in fact many thriving societies denied this. But, interestingly enough, in the founding Documents of the United States you see this ascribed to a creator.
Many people (including Atheists who deny the creator bit) accept equality as a matter of faith.
You have failed to show how the unsupported values of a hypothetical or real non-religious society are any more legitimate than the values of any religious society.