“For a variety of reasons, including brutal population pressures, people developed a cluster of traits – nonviolence, literacy, thrift and patience – that gradually became the values of society as a whole. “
They are trying to take “Cultural Traits” and Wrongfully align Genetics with their Dying Belief in the “Noble Savage” in order to save the farce that is the “Noble Savage” lie.
The "nonviolence" part of this is an expression of the bias of the "scientists."
History is pretty clear that successful societies were nonviolent within the society, or evolved to become that way, while spectacularly violent when necessary when dealing with outsiders.
Societies that were not successfully violent in their dealings with outsiders were exterminated, or enslaved and eventually assimilated.