My best guess it that there is a societal/group benefit in reducing aggression (maybe not unrelated to they way our closest DNA match, Bonobos, function). I do

My best guess it that there is a societal/group benefit in reducing aggression (maybe not unrelated to they way our closest DNA match, Bonobos, function). I don't think we're at the point yet, and certainly not in last few million years of evolution, where overpopulation is an issue, and since evolution is all about (collectively) creating the largest next-generation population, this isn't the way I would expect to see increased competition for resources to play out.