The other thing is the idea that, for those of us growing up in various segments of society that are affected by the above, our very mechanism of thought was generated by this system, and that affects how we think about and perceive these systems (and everything else).
I believe he's simply advocating for being conscious of the above two facts, when examining these systems and reforming them (and of course when teaching the history of these systems). To ignore race and racism as if it never happened is to allow all of that ingrained racism to perpetuate (of systems and of thought). All of this sounds pretty reasonable to me, but that may be due to my particular experience.
That said - I'm no expert, I've only read the linked passage so far, though I've now ordered the book and will start reading it tonight. I'll refrain from commenting further here (I think we're pretty off-topic already). Thanks for the discussion!