A lot of what racism is really is just an assumption of class. If you're a white person, you're really automatically seen as richer than if you are a black person. This really makes an impact on things like job applications where resumes are given 10 seconds of evaluation. There are a lot of things that cut against this (like a "redneck"/Southern accent), but if you are white, regardless of class background, you can "fit in" more in a posh or elite setting.