You say that as if you have unequivocal proof of that, I would like to see it.
Religious belief predates civilisation, that is a given. That we have an innate ethical compass is something that philosophers greater than you or I have been arguing over since time immemorial, if you have some insight as to how the greatest minds humanity has to offer cannot agree or prove an innate morality, yet you do I would like to hear it.
Especially when you take into consideration nihilism and what existentialists like Camus and Sartre have to say on the topic of ethics.
I think that we do have an ethical morality, but it has been ingrained by our parents and their parents before them and so on, it is a cultural and historical morality that religion had it's part to play in. Read Lord of the Flies for a glimpse at ethical behaviour among young adolescents with no controls and look at a group of children with no supervision to see just how far an innate moral compass really goes.
We are at the very base of it Animals, do Animals have a morality, or do they react and make decisions based on need and instinct only. Would a starving lion not eat their children?
If you are saying that we have some kind of innate morality, why do we differ to every other animal on Earth in this regard. Do Humans not become feral without civilisation and society to guide them?
And I am saying that they simply don't prove anything, especially when you consider the innate issues with US prison populations regarding Black and minority conviction rates, the fact that many come to religion BECAUSE they are in jail and it can lead to early parole in many states.