I like to explain it with this analogy: compare a social institution like feudalism, in which one group of people are lords and others are serfs. If a serf gets angry and kills a lord, it could be a crime, but it would be absurd to call it “reverse feudalism” — for the serf is not in a position to set up such an institution. About the only way you could have something the would deserve to be labelled “reverse feudalism” would be if some serfs set up some community of their own, in the woods like Robin Hood, say, and then kidnapped some lords and, uh, lorded over them there in various ways, perhaps as a kind of retribution.
The premise is that “racism” should be taken as a label for a social institution in which one group is on top and another on the bottom. (Mav refers to this as “systemic” racism). Since folks on the bottom of the current institutions don’t in normal circumstances have the power to actually constitute a comparable institution of “reverse racism”, that label basically makes no more sense than “reverse feudalism.”
From this point of view, sure Mav could fail white students and a man like Ronald Taylor can go into the Wilkinsburg McDonalds with the aim of killing white people. These would be wrongs, but they would also just be individual actions, not part of any institutionalized system of social oppresion — so not “reverse racism.”