Human nature has a base level which has been measured and studied in a variety of scientific ways. It then responds to circumstance, culture, etc., as demonstrated by what happend during WWII. The populations of London, Dresden, and other large cities were not made up a small hunter-gatherer bands. They were patriarchal dominance hierarchies which none-the-less experienced new levels of egalitarianism in a crisis.
I'm not arguing that we can or should try to recreate the exact conditions of small H/G bands. I'm simply making the point in both this story and the one that sparked it that there is no evidence of mass violence before the agricultural revolution. Despite all the solid analysis and supports from scientific experts, I none-the-less keep hearing from some men who are emotionally attached to the idea of constant selfish, warlike, dominance-hierarchy behaviors. This story is a response to one of them.
As I've quoted before from a World Economic Forum article, with the rise of agriculture, "Labor roles became more gendered as well. Generally, men did the majority of the fieldwork while women were relegated to child-rearing and household work. Without contributing food (and by association, without control over it), women became second-class citizens. Women also had babies more frequently, on average once every two years rather than once every four in hunter-gatherer societies.
Because somebody had to have control over surplus food, it became necessary to divide society into roles that supported this hierarchy. The roles of an administrator, a servant, a priest, and a soldier were invented. The soldier was especially important because agriculture was so unsustainable compared to hunting and gathering. The fickleness of agriculture ironically encouraged more migration into neighboring lands in search of more resources and warfare with neighboring groups. Capturing slaves was also important since farming was hard work, and more people were working in these new roles.
This division of labor and social inequality had very real consequences. For instance, while the majority of people had disastrous health compared to their hunter-gatherer ancestors, the skeletons of Mycenean royalty had better teeth and were three inches taller than their subjects. Chilean mummies from A.D. 1000 had a fourfold lower rate of bone lesions caused by disease than commoners."
Dominance hiearchies (patriarchy) arose out of needs that came with agriculture, and then proceeded to spread because they were so unequal and disruptive, driving migration (something I've provided documentation of in this OP). Proto-agricultural enclaves like Çatalhöyük took thousands of years to succumb to patriarchy, but they eventually did.
I appreciate your honest questions, but I think I've spoken to them already, in this story and others.
If you haven't already done so, you may want to read this story, which talks about partnership-oriented subcultures that exist within modern patriarchies.
