I appreciate your trying to find it. Here's the link. [1]
The guest refers to the mismatch hypothesis, described by a Supreme Court Justice, as an "arcane argument" that is "really proven not to be the case". Then the other guest on the show laughed at the Justice (Scalia) and mischaracterized his statement. According to her, Scalia believes that "African-American people are stupid".
In reality, the mismatch hypothesis is about largely about preparation level. If you have equally intelligent students with large differences in academic preparation, the student that is less well prepared is likely to be harmed (in terms of GPA, class rank, likelihood to drop a well-paying major) when surrounded by other students that are more well-prepared.
If one of the guests or the host were even vaguely familiar with the concept, this mischaracterization would have been questioned.
I would also note that it is mischaracterizations like these (Scalia thinks "African-American people are stupid"!) that lead to further polarization. I would expect partisan framing like this on some news outlets, but it's pretty sad to hear it on NPR, on a show whose name implies openness to all perspectives.
1: https://www.npr.org/2015/12/11/459392702/week-in-politics-tr...