I saw Glenn Loury on Booknotes last night as I was falling asleep. That last part is a deliberate about how much I was paying attention, but it was nonetheless interesting - perhaps more for what was left unsaid than what was said. Loury has an interesting history - Harvard Economist, African American darling of the Right, prominent member of AEI. He ran into some problems first with a drug bust at which point he left Harvard (not forced to IIRC) and then subsequently a falling out with the Right.
His decision to separate himself from AEI came after he read, and panned, D'Souza's racist screed The End of Racism , which was being highly touted by his circle at the time. It was at this point that he realized, as any honest and sane person in his position would, that at best his colleagues were uninterested in the "conservative" approach to racial issues they claimed. And, most likely, the widespread approval of the sneering condescension in D'Souza's bigoted book made him recognize just what that "conservative approach" stemmed from.
What was left unsaid had to do with the fact that his non-communication with his former pals, including Clarence Thomas, has nothing to do with an "intellectual evolution," but the simple fact that he quit the "movement."