Glad you found the reply helpful.
Regarding "but is it really mainstream": Difficult question. I believe the answer is a "yes" with many caveats and clarifications.
How to define "mainstream"? Maybe your definition is "among the entire US population, less than 10 % believe the 10-points" or something similar. I think McWhorter has another frame of reference: (non-right wing) media, (higher) education, (non-right wing) politics and a subset of economical organisations (think Silicon Valley). Within these organisations, you should not be surprised to witness an adherence to at least some of the 10-points, and receive punishment if you loudly oppose them.
A recent data point: The New York Times has fired an acclaimed science reporter (specialized on COVID, nonetheless), because in 2019 he dared to utter the N-word in the following context: A student asked him for an example of egretious racism, to which he replied with saying "If somebody said the N-word". He dared to utter the word actually, leading to the recent events (https://quillette.com/2021/02/09/with-a-star-science-reporte...). Just like in Harry Potter, the mere utterance of a word has magic effects. To me, this is literally a regression to the Dark Ages. The word is the thing, saying it out loud stirrs the evil.
Of course this is just one anecdote, but there are many similar anecdotes. At which point does it become a trend? Here it becomes important to note that there is no need for a majority to command social change. Instead, small but determined minorities are extremely successful in getting what they want. The mechanics behind that are currently a hot topic of debate (https://medium.com/incerto/the-most-intolerant-wins-the-dict...).
However, the important takeaway is that critical race theory ("white fragility") is not the only "this cannot be real" movement taking hold of universities, social media, established media outlets and politics. In places of higher education you may find yourself drastically punished if you insist that sex has a biological basis, that vocational interests are not evenly distributed between genders, that the American Civil War indeed aimed at freeing slaves, or that hiring decisions should be primarily based on merit of the applicants.
From your other comments I gathered that you are relatively new to "this", whatever this is. I suppose your priors were calibrated in a time certain tenets of humanism such as the value of truth, rationality and the universality of human experience were common place, especiall among the left. The tectonic shift we are witnessing today is that these tenets are declared to be false and even imoral, and that the proponents of such views are gaining the upper hand. I will sound dramatic, but I fear that the progress won by the period of enlightenment is in grave danger.
I probably have not convinced you that what I am saying is actually happening, but that's ok. This would take a longer discussion, there is a lot to unpack here. Perhaps you can consider it as a possibility, and adjust your priors for future events.