I do not think the article argues that Agile somehow incites racism and bias, it argues that it doesn't account for them while it should.
That explains an awful lot. When people think that it's enough that they're right, bad things happen. Agile doesn't actually need a theory of society to understand that, just a little humility.
Author misses the part where the majority of the working force is also "white men" who see no benefit from this either, because it turns out, the decisions of management aren't for "white men" or even "old white men". The decisions are for "our management".