For a long time, there has been a prejudice in the social sciences which tended to view early humans as peaceful noble savages and blame human violence on more recent social structures like capitalism, imperialism and all that. Short version: we used to be cool but now we're crap.
I'm no cheerleader for predatory capitalism or imperialism, but that view turned out to be pretty much perfectly wrong. More and more evidence indicates that the rate of violence as it affects a portion of the human population has actually decreased throughout human history. By a lot. In other words, we may be crappy now, but we were a whole lot more crappy and violent in hunter gatherer societies.
It is also now pretty well established that something like war has long existed in chimpanzee societies and that this is unrelated to human intervention.
You could view that as a downer, but I don't. It shows that we really can make progress and control our historical end evolutionary baggage to some degree. Of course, we're not there yet!