Isn’t that pretty much the same issue that comes up when the ‘civility’ request pops up in deeply problematic locations?
The “Well, yes, I agree that you may have suffered certain ill effects of institutionalized racism; but how can we have a reasonable, civil, conversation about race when you are being so shrill and angry?” adjusts David Brooks mask, oozes innocence and smarm
At the straw-man level, sure, historical objectivity is good: the “How our ancestors were issued an impeccably moral claim to whatever we currently possess, and probably more; and defeated our abhuman enemies with enough vehemence to show our resolve and badassitude; but definitely without resorting to any tactics about which I might have to feel bad” genre of ‘history’ is rightly derided, except by all the people who wallow in it; but the idea that you somehow can’t apply any ethical standards whatsoever to things that happened in the past isn’t the same thing.
A prediction.
At this point, anyone saying he wants to neutralize the conversation about slavery also means to downplay its horrors and impact on modern society. He must feel sufficiently removed and unaffected from it to consider he can argue from a neutral position.