Well, that's not quite what they're saying - essentially what they're saying is that they're a different kind of smart. Not that I agree with the logic, but essentially what they're saying is that the tests - along with the whole curriculum - were designed and written by white people, so they're unintentionally biased in a way that non-white people (except, I guess, asians) can't understand them. The implication being, of course, that if black people had designed the entire curriculum and the tests, they would be similarly impenetrable to white people. Of course, I don't think that makes much sense either, but that is the essence of what they're trying to assert.
But teaching math absolutely is not. It is a very human process, helping students find handholds in what they know to make the next conceptual step. Absolutely breaking their minds with a new topic, then returning to it a month later and they find it obvious now. There are no platonic math lesson plans out there to tap into, and finding more effective ones has been one of humanity's jobs for at least as long as there has been written language.
(FWIW, real analysis is generally considered one of the easier courses in a typical math degree)
Quite a few colleges seem to use it as a filter class to determine who has the requisite aptitude and interest in pure math. At my college, the material wasn't particularly bad, but the evaluations were designed to be pretty challenging and grades weren't curved at all.
On the other hand, in my real analysis course we worked with metric spaces, topological spaces, Hilbert spaces, the Baire Category Theorem, etc. I doubt most students in “a typical math degree” would be studying these topics outside of a pure mathematics specific degree program.
I'm pretty sure that is exactly what they are saying. The 2021 version of it anyway
What is a "white person"? A "black person"? Are these metaphysical categories? Biological categories? Cultural categories? Why would a person of one category be unable to understand curricula produced by people of another?