Empirically, the problem with the "humans are basically bad but for the 'thin veneer of civilization'" theory can be summed up simply:
"If civilization is so fragile, then WHY is it EMERGENT?"
We didn't slide to our present state from some past state of grace. We climbed here from a complete lack of civilization.
Humans are self-organizing by nature. If we have a fault, it's probably that we tend towards _too much_ order.