I think that it makes a different if God existed. But I do not believe that there is a God.

I see history and I just see that religions were created to control the masses, making wars, etc. For the government (Kingdoms) could strive more and more. Like a blindfolded into plebs eyes.

well selfish and destructive behavior has been shown to produce reproductive success in some ways -

http://www.nydailynews.com/news/national/james-holmes-fan-mail-reveals-sick-fixatation-killer-article-1.2356103

https://www.youtube.com/watch?v=OqmthnrG-2A

A lot of animals reproduce via sexual domination. If an individual is fit enough, they can force themselves on a mate, in fact, a large part of human history was/is dictated by this very principle, and now we have people that complain about the patriarchy, which is the systematic oppression and domination of the female sex by means evolved BEYOND physcial dominaton to social and psychological domination.

EDIT: I thought i should add im not disagreeing with your statement, just saying that it is not the origin of morality, at least in my view.

It does if you have a scientific mind

Very mature of you, but humans are social animals and when a belief becomes a mass religion, it dons the appearance of a culture. This is why it becomes a talking piece.

I mean, even with religion, how could you say that god's given morality is OBJECTIVELY ideal? 

I'd conest that. What proves that you don't, perhaps, only exist in the passing, the moment? That your next thought is thought is that another? It is impossible to have two concentrated, conscious thoughts at once - perhaps, the pain felt, the light seen a second ago was not felt by you, but is just accesible to your memory?

because over a long period of time we've observed what concepts lead to stable, prosperous societies/individuals and how the ignoring of those concepts have lead to the downfall of societies/individuals

in short the answer is ironically the same for our sciences - observations of what works over long periods of times repetitively 

and that's why we associated these concepts with the supernatural because they appear to transcend our limited scope of reality

concepts such as do onto others as you would have them do onto you

because god wouldve created morality. whatever one he has is probably pretty tip-top.

If that is your answer, I do not see how god needs to be implied. Morality, its purposes and effects, have been discussed extensively by many great minds. (Bentham, Mills, Kant, Rawls...)

Game theory can turn optimizing human behaviour into mathematical equations. 

No religion needed. If you say it's a science, then leave it to scientists, with more complete procedures.