The gist of the difference of opinion between what you argued and what I argued is whether humanity's morality relied and still relies on religion and/or whether morality is being furthered by religion. That seems to be your POV; I argued differently.
Rely is the wrong word. I never said that morality is dependent on religion. I said "Religion has often played an important aspect in the development of morality." Is there any religion that hasn't got a moral component? Is there any religion that hasn't played some role in the development of morality to some degree? You may think that this development was backwards, and so no development at all, but these religions did, and continue, to influence peoples' and societal morals.
So my position doesn't even consider whether morality relied or still relies on religion. It only matters that religion, for whatever reasons and at whatever time, concerned itself with morality and thus influenced the course of moral development. I submit that if this had not happened the world would have been different - but how, i could only guess.
When morality and religion intertwined, morality got dressed up in the different garments of the various religious cloaks. The underlying moral values remained pretty much standard, just presented in different narratives. Religion was not needed, it did not benefit society's moral values; on the contrary, it skewed our moral compass and aimed it at pleasuring some superstitious deity.
You seem very sure of this conclusion, so perhaps you could provide references. It's not that i'm lazy, just time poor. I quickly googled what you recommended and found some sites disagreeing with this idea, and others agreeing. A couple of archaeologists i know who say that unless you can thoroughly vet the source of information yourself take things said of the ancient world very tentatively: history is far more susceptible to bias than science. Which isn't to say that there isn't lots of valid literature out there, only that it would take more time to find the valid stuff than i have available. You seem to have already researched this, so you might know of good sources arguing for and against the idea.
Again, i'm not arguing morality needed religion to develop, only that for some time they have, for better or worse, developed together.
I am not convinced that Confucius or Buddha set out to teach religions. A form of religion (Tibetan monasteries for example) followed from their teachings.
Maybe Jesus didn't intend to start a religion. Their intentions didn't stop the fact.
The countries affected by the Age of Enlightenment are mostly secular, even though a lot of people still cling to religious traditions (cling more than practice). Most of central Europe in fact, while you can add the Scandinavian countries to that list as well. USA & UK (and South Africa) are still religious because most of their inhabitants (incl. European settlers) were never exposed to the Age of Enlightenment. A lot of them fled the violence of inter-faith persecution. They were staunch Reformers or Roman Catholics, so what else would you expect? It will take many generations for these societies to rid themselves from their religious roots, I am afraid. See my previous reference re skewed moral compasses. Not that I am branding them immoral though.
What these few examples show is that humanity does not need religion for morality. But i'm not arguing against this. I'm arguing that something like 84% of the worlds population is religious to some extent. You may believe they have a skewed moral compass - OK. We still have to interact with these people, come to decisions and make laws with them. When we engage in moral dialogue with such people they will be drawing from religious sources, and so it is incumbent upon us to understand where they are coming from. Thus the bible is still morally relevant.
And for that we need to look at what happened before the rise of (organised) religion and also how religion might have affected the natural evolvement of morality (as alluded to by other posters). Again, IMO religion was not a prerequisite for the furtherance of morality among our species, in many cases it was a hindrance.
I agree it was not a necessary prerequisite, but it is the direction our history took. Whether that was a hindrance or not can only be conjecture. We cannot repeat the experiment of humanity so we'll never really know. I think the only relevant question is what religion can do for humanity now and in the future - and if it offers nothing how can we, as a species, put it down?