I found Sandra Schmuhl Long's White People Need to Reckon With Atticus Finch’s Racism, but I'm afraid more as an example of how slipping uncritically into cliches and sloppy classifications turns everything into microwaved mush. A few points.
(1) The use of the classification 'white people' is clickbaity but dishonest. People who have never read To Kill a Mockingbird certainly have no need to concern themselves with these matters, regardless of their race. It would have to be readers of To Kill a Mockingbird, not 'white people'. Perhaps it would be white readers especially, but Long doesn't really establish this and arguably fails to do justice to readers who have reckoned with it. It's just sloppiness all around.
(2) But it goes even beyond that. Go Set a Watchman is not (as it was originally billed) a sequel to To Kill a Mockingbird; the evidence has become quite clear that it was the earlier draft version. That is, you can perfectly well just read To Kill a Mockingbird; nothing about reading that requires structurally or narratively that you read Go Set a Watchman. Nothing about reading a final version requires that you read the original version from which it came. And the Atticus Finch is not (contrary to Long's fiat proclamation) "the same Atticus"; it is literally a different version of the character in a different version of the novel. There is no "character arc" over the two books. Each book has a different character arc, and Go Set a Watchman is more like an alternate history than a consequence of To Kill a Mockingbird.
(3) Nor (as Long concedes) is there any room to doubt that, of the two, To Kill a Mockingbird is the superior work in literary terms. It is even superior to Go Set a Watchman if we just look at how it addresses racism -- Go Set a Watchman has racism as a theme, but it is not about racism, but about father-daughter relations. Racism in the original vision for the book was just the crisis-producing occasion for exploring the latter. Long gets this completely wrong, saying that "It’s a book about race that tries to convince its reader it’s about something else entirely" -- no, it's a book about something else entirely that uses race as a plot device. As it was re-written into To Kill a Mockingbird, the father-daughter relationship was made less tangled, allowing for a more universally accessible portrayal of racism and the heroism of fighting it. Go Set a Watchman has some interesting features; it is, however, an awkward first attempt, and there is nothing whatsoever surprising or troublesome if people don't like it and choose to ignore it.
(4) It's ironic that, for all the pumping-up of Go Set a Watchman, Long's essay reiterates the version of progressivism that Go Set a Watchman quite clearly criticizes. Jean Louise's problem is that she affirms progressive ideals but also wants to her father's progressivism to be an eternal exemplar. This is a contradiction; the former requires that every step in the progress be conditioned, the latter does not. She has not learned the adult version of progressivism (which her father shows that he already knows) that progress eventually leaves everyone behind: the heroes of yesterday were just ordinary, flawed people who took a step, and progress will step beyond them. Progress leaves everyone behind, and a genuine commitment to progress requires fully recognizing that. What Long does in her essay is retread Jean Louise's mistake by treating Atticus's provinicialism and blindness to broader issues as a scandal precisely because Atticus does not live up to an entirely mythological version of her father (and thus civil rights heroes generally) that Jean Louise has made up in her head -- a mistake that the novel clearly depicts as a childish one that needs to be overcome for maturity.
