Explaining The NYT's "1619 Project"

I actually find the NYT's "1619 Project" interesting. Not because I find its main theses plausible--I found them implausible from the beginning, though I admitted that I could be convinced if the historical arguments were there. Rather, I find the thing interesting because:
(a) The main theses are implausible and false
and
(b) Given (a), we need an explanation of the NYT's decision to undertake the project / give it the form it has.
   If the main theses were true--or even false but plausible--that's all the explanation we would need. The best explanation for my neighbor's belief that there's a cherry tree in my backyard is that there's a cherry tree in my backyard. But, traditionally, if someone believes or does something that can't be explained in terms of truth and/or plausibility, we've got to go psychological (which can also mean: sociological).
   Why on earth would somebody try to make slavery out to be the fact at the center of the story of America? Why would they ignore all the good...focus on what is arguably the worst...and try to twist it into being what is most important?
   Why...oh, why...?
   Answering that question is left as an exercise for the reader.