Before responding, I should note that I am an agnostic atheist since I believe that god cannot be disproven, but is most likely believed in because of human need. Most of your questions can be traced back to the golden rule, which is enforced naturally among humans. In the animal kingdom you might say the rule is might makes right. However when dealing with intelligent beings this transforms into the golden rule. All humans are equally mighty when ingenuity is considered. Therefore an imbalance of numbers and therefore might occurs only when one person tries to benefit at the expense of others. IE the golden rule is enforced. Sympathy for people you might hurt by breaking the golden rule is secondary to the effect that the belief that you will suffer if you try it has on a person. Sympathy is a way to get what you want from people when you just can't take it.