But primarily, right? Bias plays a role, so everything else being equal, a black applicant will receive fewer callbacks than a white or asian one, but (and that's a big but) the primary issue is that usually not all other things are equal.

The average black person comes from a different socioeconomic background than the average white or asian person, so they'll usually not have the same level of education, but less so because of being discriminated against because of their race, but because of their class. More single-parent households, lower household income, their parents can't simply afford to hire tutors and put them through college etc etc.

That's what makes these things somewhat weird. Yeah, sure, a black guy from a rich family that attended MIT will have a harder time finding funding than his white or asian friends from the same background ... but he'll have a much easier time than some white kid from a broken home.

I believe two things to be true: class is the primary factor, not race. And it's more convenient to focus on race because it's much easier and feels less threatening to the (usually upper middle class and beyond) proponents. "We (as white people) need to share more" puts them in a group with (for the US) 60% of the population and is pretty abstract. Great for virtue signalling, terrible for concrete actions. "We (as rich people) need to share more" puts them in a much, much smaller group and suggests they could actually do something besides yelling at people to check their privilege: share some of the money they inherit. Great for doing something, terrible for virtue signalling because "well, put your money where your mouth is" is so obvious.