It is a real thing. On the other side, I am a black female who grew up in middle class suburbia and has a typical Bay Area accent. This affords me a level of privilege because I can easily "class pass" as someone more affluent - even though it is generally assumed black people are lower class. This means I have the "right" mannerisms and speaking patterns for corporate jobs and other things and it is easier for me to be perceived as a good culture fit because I have the right class markers.
It also meant, particularly earlier in my career before social media, I would get some interviews and then the interviewer was shocked I was black when I showed up.
Yea I think everyone has some sense that this is still prevalent, but at least in my case, it was easy enough to wave away as only true in dramatic cases, like discrimination against AAVE. I was mostly shocked at how finely-tuned people's detection of this kind of thing was: I doubt my lower middle class friends (otherwise very similar to me in level of education, ethnic background, etc) were explicitly and intentionally enforcing class conformity, as opposed to unthinkingly enforcing a social script that they've absorbed.
