That being said...
This article is the very definition of a straw man. Absolutely no one subscribes to the position it critiques.
On the other hand, a fair number of people (including myself) subscribe to the position that, although things are not nearly as bad as they have been in the past, there is still a latent undercurrent of actual racism in the U.S. which sometimes bubbles to the surface and manifests itself in various harmful ways, up to and including (but far from limited to) black people being systematically disenfranchised, and publicly tortured and killed by authorities, often with impunity. To people like me, straw-man arguments like the one in TFA (and F does not stand for Fine in this case) are offensive because I of course agree that the position being critiqued is risible. Whether or not it was the author's intent, some people will surely read it as saying, tacitly, there is no problem, and anyone who says there is a problem is being hysterical or otherwise detached from reality.
Well, there is a problem, and there has been for hundreds of years. We have made a lot of progress towards solving this problem. But we have not yet solved fully solved it, and anyone who says that we have, particularly when they say it in such a condescending way, is part of the problem.
[UPDATE] A lot of people are disputing my claim here. What no one has yet done is provide an actual reference to anyone going on the record to endorse the ten-point position that McWhorter calls "third-wave anti-racism." Lots of anecdotes. Zero data.