I've heard this "generations of abuse" argument before to explain the low socioeconimic status of blacks in America and natives in other countries. But is there any evidence for it other than "blame the more successful class"?

I know behaviors are passed between generations - keeping poor people's children poor, violent people's children violent, etc. But does it really work over hundreds of years? Without evidence it's nothing more than an excuse.

There's also the political correctness phenomenon of being allowed to blame metabolism for racial differences but not another genetic factor - inherited intellectual differences. It even makes some sense that there should be differences - a small group of people who evolved over 1000 years through tribal fighting might end up mentally or intellectually different from others who lived in larger social groups with relatively non-violent lives. It's quite possible that in some societies, intellectuals are systematically filtered out of the gene pool while in others, violent people are. See for instance the Ashkenazi Jews https://en.wikipedia.org/wiki/Ashkenazi_Jewish_intelligence