You are made of meat (before you are made of paperclips. Don’t worry about the paperclips until you complete your daily quota of considering your carcass weight)
Animals kill for resource competition; resources remain constrained, and humans remain clever and bloodthirsty enough to do the same in more complex environments.
War bands and warlordism is the lowest common denominator basic unit of human society, not the nuclear family. As social units go, the nuclear family is shockingly egalitarian and low-attack surface, geographically mobile and hence agile and resilient compared to other social units, in an environment of restricted kinetic engagement, freedom of movement, and primarily economic competition. The nuclear family is based on the assumption of sufficient resource availability and sufficient threat of violence from the state to prevent war bands from forming and seizing resources from lone men. (To war bands, women are resources. Children can be resources too, as forced labor, slaves [sex, mobile trade goods, or both], adoptees, or small soldiers or weapons).
The thing is, living under a state that prevents warlordism actually is a better deal for 99.9% of the population, and even smart would-be warlords prefer to live in a world in which they can grow old in comfort, surrounded by their grandchildren, consensual fuck buddies, or both, rather than inevitably being killed by a rival, one of the huge number of people he’s harmed and otherwise pissed off, or some combination of both when an immediate family member does him in.
