People on the left constantly underestimate the value of racial hierarchy is to lower class whites. Being above a minority is something that is worth dying for, because they might be poor too, but to them it is better than being a minority. That is why they rather die than have minorities become more prosperous, if minorities become that way, they have no one to be superior too.
People say that lower class whites vote against their interests. That is partially true - they vote against their economic interests , so that they can can maintain their place in the racial hierarchy. They aren't necessary wrong if you think about how this country treats minorities, especially poor minorities. Sure that lower class whites get fucked over by the rich, but it is nowhere near as bad for many minorities. That is why liberals and progressives are somewhat wasting their time trying to convince the white working class to be vote for them. The white working class is on a completely different mindset that I don't think many on the left will accept the reality of it.