The morality of Atheists is blind, because it is not guided by the One who created them. Your morality depends on what society teaches you.
It goes a little deeper than that. It stems primarily from senses of empathy and fairness, which are evolved into us, hard coded, and not totally unique to our species. Empathy means seeing yourself in others, identifying with them, and feeling their pain and suffering (even literally - see mirror neuron research). The dark side of that is tribalism. We have an easier time feeling empathy for those who we most identify with. This is explains why people care more about their children than their neighbours and more about their neighbours than strangers, and more about strangers from their country than strangers from other countries. The very dark side of that is things like racism, homophobia, islamophobia, and other groupings of us vs them, and in a religious context it can be taken all the way to "don't take kafir as friends" or "infidels should burn in hell for not believing as we do". Both sides of this Empathy/Tribalism dynamic can be found in all of us, and it varies from person to person which side is stronger. it also explains why people who hold identical texts holy can read them so very differently, setting aside parts as analogy or simply ignoring them, while emphasizing other parts as key. You don't meet many Jews who worry about wearing mixed fibres or eating shellfish today, and not many of them go around stoning people to death for various infractions, as their holy text tells them to.
If your society tells you having polygamous relations without committing to marriage is ok, you take it as right. When it tells you charging interest on loans and making poor go poorer is ok, you accept it as ok.
Social norms, peer pressure, and other social forces do definitely play a role. Religion is key amongst them. At the end of the day though, the empathy and fairness instincts can prevail, and logic and reason can be applied, if we don't blind ourselves with adherence to some externally applied code and think things through for ourselves. Personally, I will revise my position on various social issues, and have done so on more than one occasion as I gain better data and think or hear better arguments. Should polygamy be ok? Should usury? I can see arguments on both sides of both of those issues and I don't blindly follow any dictator of thought or belief.
But our morality is guided by the One who knows everything. His wisdom encompasses everything.
As I wrote earlier in this thread, if you truly do have a God who knows all, and who is perfectly benevolent towards you, which is awfully hard to explain given the world we live in, with natural disasters and disease and animals that can only survive and reproduce by eating others from the inside out, then you have a point. And, as I was forced to earlier in this thread by an admin, I grant you that Allah is perfect and wise and just and benevolent, etc etc. Horray, your forum rules make you win a no-prize.
But that doesn't undo my point earlier in this thread in any way, because there are OTHER "gods": FALSE Gods. There are followers of those false Gods who believe just as strongly as you do that anything they think their false God is telling them to do must be good and just, even if they can't see why or how. They follow the exact same reasoning you do, in shutting off or overriding their own internal moral senses of empathy and fairness, because surely their (false) god knows better than they do, and so they believe some truly horrible things and engage in some truly horrible behaviour thinking it just and good. Everything from forcing poisoned Koolaid on children, to murdering people who they think are possesed by demons, to "witch" burnings, to hanging homosexuals, to flying planes into buildings, and on and on it goes. And you can't reason with these people once they have farmed their moral decision making out. They have made themselves into well meaning monsters.
Note that religion isn't the only reason farm out their moral decision making. This can happen in a secular context as well. We should be weary to defer moral decision making to any leader, real or imagined. Obedience is not in and of itself morality, and in fact it is often its opposite.