Right explanation, wrong name.
Nicholas Kristoff has a good column with a wrong name
"Racism Without Racists" is the title. It focuses on the fact that explicit racism is much less rare, and that discrimination occurs by whites who are not racist. That is to say, they do not consciously view other races as "inferior."
The phenomena is called "aversive racism."
This is something I have been talking about for some years, but it is a dumb and misleading name. What we are seeing, and is bluntly far more useful to talk about if one wishes to actually do
something about it, is tribalism.
Tribalism is the rather basic idea that people respond better to other people with whom they feel a kinship, and may regard those of another tribe (those whom they identify as "other") with suspicion. It is present to a greater or lesse degree in all human beings. As Heinlien described so well in Citizen of the Galaxy
: "Every culture has a word that translates to 'me, my wife, my children, my brother and his wife and kids, and no one else.'" We have multiple tribes in which we are members. Ever sing "Weekend Only World" or "Harry's Song" or any other "gosh aren't we in fandom great and wonderful together and mundanes are just stooopid?" That's tribalism.
Triablism comes in big and little flavors and is extremely flexible and expansive. Show me a resume that has two equal candidates but one went to Princeton and another went to a different college and odds are good I will favor the Princeton resume. But if there are obvious differences that go to fitness, those differences win out.
I find this formulation much more effective than the racism formulation because (a) it applies more broadly, and (b) "racism" is one of those major power words that makes intelligent conversation on the subject impossible.