[abalone]

That's not really accurate. Chomsky's "key statement" at the very beginning of the thread refers to studies that have demonstrated "white supremacy that is more rampant here even than it was in apartheid South Africa." That, despite the experience of racism being a naked fact that anyone with eyes can see should they make a modicum of effort to break out of their "white racist cocoon". But these studies would presumably detail how white supremacy works, for those that need it explained.

He implies that these studies are readily available, alongside "a huge literature of professional criminology," for anyone willing to look. What he's facing here is an interlocutor that isn't interested in doing the research or following logic, just citing right-wing op-eds.