You make a lot of good points, although there is no evidence of any sort of mass human violence before 13,000 years ago. Of course, individuals killed each other from time to time, but that's not the same as a culture of killing "the other." In fact, there's a lot of anthropological evidence that helping each other -either within the tribe, or even with neighboring tribes (who intentionally and deliberately intermarried) was the main survivial mechanism in an unforgiving natural world that none-the-less had low population density and plenty of natural resources. In other words, there wasn't really anything to fight over - until about 13K years ago, when there was.

Finding a way back toward a more egalitarian social structure where we use taking care of each other as a part of our survival strategy won't be easy, but I can definitely see where humor that doesn't punch down could be a part of that.