@averroes,
How can man remove himself from nature at all? One cannot remove ones self from the natural world through reason or any other means.
It is useful for us to categorize, analyze, and otherwise group things according to the specific characteristics we observe. When we observe something that seems contrary to our perception of what it should be, we might say it is unnatural when we really should be saying it is unusual (outside of normal tendencies).
As a cat behaves as a cat, and a dog as a dog, It is mans nature to be exactly as he is. Good and evil are only judgments, constructs of the mind, and neither of these is any more or less our nature.
It is my opinion that removing ourselves from nature (through religious ideas mostly) has an obscurant affect. By hiding or denying our natural primate tendencies we misunderstand our very nature. I feel that we are the way we are (our nature or tendencies) to a large extent as a result of our history. Selection pressure and the resulting adaptations have molded us.
Should we be surprised that the top primate has selfish, violent, warmongering tendencies? The human characteristic tendencies, good or bad, are present because selection pressure favored those characteristics. We cannot so quickly turn from those traits even if the selection pressure that developed them has waned. Sadly, it appears that man cannot reason away the traits we so disdain in ourselves.