There is a correlation between economic inequality and personal violence. The explanation for the correlation isn't completely clear; there are a number of possibilities.
We're a miserably violent species. But there's a complication, which is we don't hate violence, we hate the wrong kind. And when it's the right kind, we cheer it on, we hand out medals, we vote for, we mate with our champions of it. When it's the right kind of violence, we love it.