That phenomenon has been studied in first generation college students, it's real.
Parents who didn't go to college don't have the experience to give specific advice on anything related to it, whether appying, or even about college life.
Parents who have done so, can. And knowledge is power.
I suspect this is affecting these gifted programs we're discussing. Though as a practical matter it's probably more of a socio-economic bias than racial. It just so happens that fewer white people are among the lowest social economic rungs of the ladder.
There's probably similar results in poor and/or working class rural blue collar towns. Having lived in such towns said issues are obvious.
You don't see very many (if any at all) poor kids on the yearbook staff, or be a part of a foreign exchange program. And you won't see them at all in Band. (though you will in chorus/glee club) You won't see many in National Honor Society either, part of that is extracurriculars are part of the qualifications at most schools. Fewer extracurriculars due to income means you're less likely to get in.
And in case people don't realize it, smaller poorer schools tend to charge fees for extracurriculars, even non-sports ones. (Sometimes even yearly registration AND book fees, which are sometimes not subsidized for poorer kids.) Sometimes a school district can be actively hostile to lower income students (in these cases it's usually a jerkass administrator who sees poverty as a moral flaw and wants to punish poor people thinking the punishment will be an incentive)
I personally have seen these things. For example, I know of a school that once required it's yearly fee and book fee as a lump sum, and if one didn't have the cash, well the official policy was that the student could not attend till they were paid. But also that attendance was compulsory and lack of such attendance would be considered a truancy violation by both parent and student and law inforcement would be informed.
It was total whack. I think a bunch of people complained and IIRC some phone calls were made to and by government officials and the district backed down a bit. (IIRC it involved splitting up the payments and/or reduced book fees. Apparently they were supposed to be doing that already, but weren't.)
Also sometimes poor kids might get opportunities, that they can't actually take advantage of because they don't have the money to do so.
In my junior year I and my parents were called in to the guidance counselors office. Didn't know what for. The counselor suprised us by saying that the state was starting a new science/math centric school for gifted students and that I qualified for/and was guaranteed a slot for my senior year and that is was a great opportunity. He asked if we were interested....we said yes. My parents asked about cost and the counselor said zero, no fees, zippo. But then he stated that transportatoin would be required. This school was 2 hours away at least. My parents said, if it was a state school, shouldn't they be required to transport? The counselor said no. They asked if there were dorms...the counselor said that might happen in the future. My parents then asked if I could stay with one of the teachers, that they would be okay with that. The counselor directly said that "it was not allowed." He then asked if my parents knew anybody who lived near the school or had a job near the school who could take me back and forth. My parents replied. "what kind of idiot would live down here and have a job two hours away" and directly asked him if HE knew anyone local who commuted that kind of distance.every day. Which he didn't. He then said that if I couldn't take the slot it would have to go to someone else (and not even someone else from my school), and they had to sign a paper giving up the slot. They then asked what the hell kind of school was this to not take into account students not living close by and/or poor kids, and that it was a shitty thing to offer an opportunity that he should have known we couldn't take.
As an aside, if people don't believe in inherited privilege... well the local regional superintendent of schools is the son of the previous superintendent. This is an ELECTED office mind you and I'm pretty sure our country was originally opposed to inheritance of political power and titles. and yes, I'm opposed to ANY relative of an officeholder holding the same office, or preferably any elected office at all. And I think that ban should extend to 3 generations at least.