Juma said:
Thus showing that behavior can be said to be immoral without any god will destroy the theists argument.
Yes, of course it would (as long as the "can be said" means "can be truthfully said"). But you said "It shows how something is moral without the need of a god."
You did not say that it shows that something is
immoral without the need of a god.
Again, the word "moral" is quite ambiguous, but if by "moral" you mean "morally permissible", well, some theists are claiming that
everything is permissible if God does not exist, so showing that something is permissible would be no objection.
On the other hand, if you meant "morally obligatory", then that would work (indirectly or directly depending of the specifics of the theistic metaethical argument you're going up against), but in that case, my questions were:
a. How would morality as social concordance shows that something is morally obligatory?
b. What does "morality as social concordance" even means?
As it happens, fromderinside already explained what he meant, and I already replied to him. But if you think that his answer somehow shows that something can be immoral without God, then please explain.
That said, if you're trying that something can be immoral without God, then at least you are on the right path on that point. That's what the argument really is about. But the best strategy is to reject the burden, say there is no particular reason to even suspect that nothing can be immoral if God does not exist, say the atheists who say otherwise are very mistaken, and address the theistic arguments one by one ("arguments" as in "arguing a case"), showing why they're bad ones.