Have you looked at Europe or Africa - 2000 BC to 1970?
Oh - and the Native americans were pretty violent against eachother before the slaughter by colonisation:
"Despite the myth that Aboriginals lived in happy harmony before the arrival of Europeans, war was central to the way of life of many First Nation cultures."
Warfare In Pre-Columbian North America - Canada.ca
The history of indigenous military activity, prior to the arrival of Europeans.www.canada.ca
That’ a straw man. The myth is they lived in harmony will the land not each other. No one lived in harmony with each other at that time. Conquest and war were everyday life. Its only in recent times the idea that you can extract just as much wealth and power by keeping peace, began to flourish. Prior to that (wether it was reality or limited human thinking) that there were just interstitial periods of peace.