The root of human nature is our sociability . Humans need and desire association with our own kind, which forms the basis for our whole society. We're just all isolated sociopaths bouncing around, awaiting opportunities to slay, maim, dominate, and control. There is no society, just individuals. But this seems a self-serving, spurious idea to me.
People help each other all the time, in manifold ways.
In fact, it takes a degree of socialization to dull that human instinct for solidarity. A positive view of people is doubly empowering, because it provides a framework with which to understand our society. It allows you to begin focusing on structures and systems, rather than blaming individuals for the wrong they do. The other road is to simply throw your hands skyward and give up on humanity as too evil, too wicked, or too foolish to ever mend our ways. The next time you hear someone blow off humanity, try challenging them to explain why a person would do such a thing.