You do not know anyone’s nature but your own. You cannot assume anyone’s behavior except your own. By definition, you are entirely wrong, because your entire conception is based upon assumptions about people you’ve never met and likely never will. You are definitively the narcissist in this thread, making everything about you. You need to pull the tapeworm out of your ass.
Humanity’s common nature, beyond the last few hundred years, is actually one of mutual aid and cooperation. I’d encourage you to look into the various Peoples Histories of the various parts of the world. It is increasingly clear the more data is gathered that the current system of elevating greed, avarice, selfishness etc, is a historical outlier on a history that stretches back hundreds of thousands of years of people collectively cooperating.