Religions split themselves into sects and levels of understanding, so it's not as if there were only one tradition holding together an entire ancient religious institution. And some religious traditions can be more virtually atheistic than others.

But sure, esoteric theists answer to their traditions, and most atheists answer to nature and to the traditions of liberal or Confucian culture. Esoteric theists tend to be more individualistic than the herd, though. Indeed, their inventiveness often borders on heresy.