It seems like the argument may come from C. K. Raju. See this 2017 article in the Journal of Black Studies, "Black Thoughts Matter: Decolonized Math, Academic C

It seems like the argument may come from C. K. Raju. See this 2017 article in the Journal of Black Studies, "Black Thoughts Matter: Decolonized Math, Academic Censorship, and the "Pythagorean" Proposition", https://www.jstor.org/stable/26174222 https://www.jstor.org/stable/26174222 It's readable with a free JSTOR account, which might be worth it if you really care to understand the scholarly arguments, such as they are. At the very least, nobody will be able to say that you don't understand this particular argument.