Below The Fold ...

[sear]

"But what I have read from anthropologists, is that humans naturally or normally do not compete." R5 #480

Fine.
BUT !

We still benefit from being alert when meeting strangers, because while the probability that they'll be lethally aggressive may be low, the consequence is reciprocally high.

"What I have read says that humanoid primates originally were arboreal, but for some reason came down from the trees.
And when they did, they discovered that by not having speed, armor, claws, or fangs, our only means of survival left was to act as a group defense." R5 #480

R5,
As you know, anthropologists weren't there then.
So they're trying to deduce behavior from fragmentary skeletons, stone tools, etc.

I'm guessing (wildly?) anthropologists generally do a pretty accurate job. BUT !
It's unlikely they're 100% correct on every detail.

I suspect our ancestors descended from the trees to strut upon the savanna imparting competitive advantage to the strutters, (otherwise we'd still be in the trees)
perhaps a more diverse diet, perhaps better more diverse mating opportunity, perhaps longer life, thus more mating opportunities, or superior child rearing.
That's speculation. We may not know why. But we know it happened.

"Meaning that when one is attacked, all have to pitch in with the defense, even though that could mean the sacrifice of your own life, in order to help someone else." R5

Their division of labor was confined to family / clan scale.
Difficult for me to imagine a crowd marching up & down the savanna. It almost certainly happened. Whether it was the rule, or the exception, who knows?

"Instead of the nuclear family arrangement we expect from our European ancestry, the natives of the Western Hemisphere lived communally.
They shared a common kiva living structure, that only had 2 or 3 cooking facilities for over 500 people.
Meaning that we are forcing a far more narcissistic society on humanity than what was naturally selected for over the millions of years of primate existence." R5 #480

I deduce you have personally visited some of these sites.
I appreciate your reflection on the experience.
I don't mean to diminish or disparage "book learnin'".
But it's difficult to substitute for personal experience.