I think that's delusional. If, as the hardened atheist believes, people are simply the result of random processes in a closed universe, then the only conceivable morality is complete hedonism: whatever is good for the atheist is moral, and murdering anybody else that gets in the way is just good business. You have to take their philosophy all the way to where it leads. It leads to mass murder, genocide, and infanticide, which are all things they support.
Not necessarily. If someone rejects that there is a creator and that this is all a result of chaos and evolution, then the ideal of "survival of the fittest" MUST take into account what is and has been shown to benefit civilization the most. If they are being objective, then killing innocent unborn human beings is AGAINST that. Having an intact family unit - mother, father, children - benefits society. There aren't any legitimate studies that dispute this. Hedonism is destructive to civilization.