Evolution accounts for co-operation, but it equally accounts for violent competition. You're partially right, having a genetic pre-disposition to excel at co-operation would have enabled our early ancestors to depend on each other for survival in times of peace which would have allowed them to survive their environment, in spite of their lack of physiological benefit (claws, fangs fur, ect.). Humans
are pack animals, but resources (food, mates, ect.) have always been limited, staying alive has generally always been very difficult. We evolved under circumstances which would put us in direct competition with other tribes for resources that
our tribe needs to survive. If our tribe had people in it who were willing to kill and enact cruelties then we stood the better chance of winning. What you call "good" was most beneficial to our ancestors when resources were plentiful, and what you call "evil" was most beneficial when resources were scarce and they had to kill the other in order to have enough to survive. Well, we warred a lot and that's how these genes would have came to be perpetuated. Plus I don't think I need to explain the benefit of rape in passing on one's genetic information, but I guess I will if you want me to. This is all disturbing, but that doesn't make it any less true.
In good or ideal circumstances, yes. We live in good circumstances right now which is why we're able to have this conversation, but most humans that have ever lived have not, and we're their offspring. It sounds like you're either operating under the
naturalistic fallacy (
what is natural is always "good") or a religious belief that "good" and "bad" come from a larger source than genetic inheritance. It's fine if it's religion, but call a spade a spade.
However, taking all that I've said into account it's still important to note that we are higher cognitive beings, the first on Earth actually - we aren't slaves to our genetics. To assume that because we evolved with violent genes we are destined to act violently would be
deterministic fallacy. We're humans, so we have rational minds that we're free to exercise once theyve benn properly fed and watered. Rationally, we have come to realize over the years that humans tend to not act excessively cruel or violent in times of plentiful resources. When societies have their act together normal people aren't forced into acting violently and naturally violent people are suppressed, so the key to living peacefully and prosperously is to ensure that no humans are forced into impoverished situations.
That's what we have to focus on, not impotent rage at dead people and other useless sentiments.
Also I'd just like to quickly mention that I don't want to talk about Hitler. This is intended to be a thread aside regarding evolutionary theory in regards to human morality.