« Humans evolved to cooperate and help each other »? False. An animal is an independent entity from the others, fundamentally individualistic, facing all that is not him, an environment that can be called the « collective » at large. In this collective the animal can obviously find independent entities that support more his individuality than others. You thought immediately congeners. But this is far from being restrictive. We are formed of viral and bacterial symbioses. We partnered with other species, called « domestic ». Even within the human species, mutual help is much stronger in the family circle than in a neighborhood, a city, a country. In summary the individual lives in a collective and cooperative relations he has with are stratified, up to reverse: caring becomes rivalry and power struggle, when the passage of one stratum to another makes resources anemic so that it is not possible to give satisfaction to everybody.
We actually own collectivist impulses. However, their role is to improve the realization of the individual through the collective. We can go up to sublimate our individuality in the collective, for example by sacrificing our life to others. The reason is not that we give up our individuality. Our self, in full consciousness, has a temporal dimension. When our self-image extends into the future, the only hope she can have for persistence is based on the collective: our offspring, our clan, our fans, the successors of our thinking. So we sublimate our individuality in eternity of the collective.
The individualistic impulse is the most fundamental. A human with whom it goes out is not a nice person but a depressive, someone who contemplate the horizon with a blank eye all day long. Individualism leads us to build original representations of the world, to attract resources, and try to impose our existence, our vision. « I am ». Ouch! Others « are » too. Not identical. A competition for power is inevitable. This competition is fundamental to push the self-organized beings we are to improve their performances and thus the effectiveness of their behavior. Violence is synonymous with competition. It becomes less physical, more psychological, according to social codes increasingly precise that dominate our lives. This development comes from two growing factors: knowledge and population density. But violence, all forms, does not disappear from our societies because they push increasingly individualism, the right to existence and importance. It is a necessity of social self-organization, whose only unavoidable principle is conflict, the conflict of the individual against the collective. Organization is a conflict management, and progress the development of a superior organization that oversees earlier ones.