I think it is, in the sense that the US is a country founded on one group of people imprisoning and disposessing other groups of people for economic profit, with those groups differentiated by ethnicity. But NOT if you're suggesting that a place with a hetereogenous ethnic or cultural makeup is neccesarily more violent or something.
Also, in fact, when you say "in other places with X, the incarceration rate doesn't seem to be as high", X can be _anything_. The US has the highest incarceration rate on the planet, by a fairly wide margin. So in EVERY other place, with any characteristic at all, the incarceration rate isn't as high. Not in Scandinavia, not in China, not in any part of Africa, not in Mexico, not anywhere. The US is alone.
In Europe, and other places/countries with more homogeneous ethnic makeups, the incarceration doesn't seem to be that high. Scandinavia, for example.