I just think this notion of codifying "white hate" seems ill-defined in terms of exactly what it would ascertain and even wobblier in terms of what would be done with it.

How could anyone be against a quantifiable contribution to historical and sociological study? I just think the OP was being disingenuous about its use, that some people who have piled on have misguided about what could/should be done with it, and that there are more useful pursuits toward the more worthy goals (historical understanding, reparations, etc).