We don’t know what Adorno or Horkheimer would have thought of today’s “critical race theory.” In their last years they were very pessimistic about the possibility of political change. They didn’t care for the student radicals of the Sixties and retreated more and more into abstract speculation. Marcuse, though, might be more supportive.
It's actually as silly as it sounds, a form of revolutionary hair-splitting that reminds us of Monty Python's People's League of Judea versus the Judean People's League, but the adherents take such distinctions very seriously indeed and are willing to shoot one another over them. They certainly did in revolutionary Russia.