Violence and human nature

According to the NYT:
"The scene was a lagoon on the shore of Lake Turkana in Kenya. The time about 10,000 years ago. One group of hunter-gatherers attacked and slaughtered another, leaving the dead with crushed skulls, embedded arrow or spear points, and other devastating wounds. . . . Violence has always been part of human behavior." Most scientists see aggression and violence as part of our evolutionary heritage.  Some anarchists and idealists believe government is the ultimate cause.  Doesn't look like it to me.