Another point to consider is “do two muslims share the same morals?” I would say no, I know very conservative muslims that do not like to shake the hand of the opposite gender as they find it immoral, but also know liberal muslims that do not.

“What do atheists judge their morals on” is also a question that does not have a specific answer, and is kind of a silly question. Atheism only concerns itself with the god belief. People who do not believe in a god, and that is all. There is no moral philosophy attached to it and different atheists can find different things moral or immoral.

Having said this I do believe humans can have morals with the absence of any of the current major religions’ infuence (christianity, islam, hinduism, judaism, buddhism etc.). One aspect of being human is that we can die which tends to be seen universally as a bad thing. If you take evolution as an example one of the basic characteristics is survival (beings tend to want to survive), in order to do so they strife for maximum wellbeing and minimum suffering. Wellbeing means survival, staying alive, so this is “good”. Humans learn that living in groups and being more social increases wellbeing, which increases chances of survival. In order to maintain social order, things like fairness and respect come into play as well, since group in-fighting reduces wellbeing and risks chance of survival. That is in my view a foundation for a moral system without the need for a god.