The link also mischaracterises the argument that anthropologists make: they do not believe that foragers had a fundamentally different ("noble savage in a Marxist feminist garden") character than moderns, but that their incentives and constraints differed. It is hard to find people to war with if you are living at extremely low population density, or to carry out ambush raids along long sightlines in the savannah. You are probably less likely to murder your neighbours' children if they are your nieces, or fail to share food with your brother's wife. Hunter-gatherer social technology exploiting human biases (e.g. toward kin) is often ignored in favour of wishful retrocasting of our own political viewpoints.
Globally, foragers may not have enjoyed the low levels of violence we do in modern society, but they may have been competitive with gardening/agricultural/tribal/state societies for millennia.