Even personal property alone leads to greed and envy, which lead to suffering and eventually violence. Communism is not magic in this regard, nor is it the proper solution. There will always be a bully out to take your lunch money, at least with capitalism and representative democracy we're able to acknowledge that and try to rein in that aspect of human nature.
Citation needed. You'd need to find a group who lived completely outside of capitalism their entire lives and yet still exhibit these bad behaviors. And as it happens, lots of such examples exist. They don't bolster your assertion though.
This group lived outside of governance for 2 millennia and don't seem to have what you call "human nature". The fact is, our nature is partially "human nature" and partially a product of our environment. No one knows how much those two things contribute so you can't say "X is human nature". We don't really know and it's not easy to test. But capitalism doesn't exist everywhere and doesn't spontaneously pop up everywhere. What is true, however, is that capitalism seems to rely on continuous growth so they eventually encroach on non-capitalists and "convert" them.