You are correct, the general gist is they believe math instruction as racist, although they do at times make reference "Western math" and "Eurocentric math", whatever that is, and not math education, so it's a bit muddled. Regardless, take 15 minutes for yourself and you will see exactly how absurd the entire premise is. Here, on how word problems support white-supremacy:

> Often the emphasis is placed on learning math in the “real world,” as if our classrooms are not a part of the real world. This reinforces notions of either/or thinking because math is only seen as useful when it is in a particular context. However, this can result in using mathematics to uphold capitalist and imperialist ways of being and understandings of the world.

Repeat that for 83 pages. It's utterly surreal.