This answer is going to seem harsh, but …
I would urge you to try harder to understand the backlash, because from the way you’ve worded your question (“Surely no one thinks …”), you seem to be trying a little too hard to not understand the backlash. Admittedly, the backlash is a tad premature since there is technically no show to watch and make our own judgments. The backlash is really about the press release from HBO, which essentially said: We’re going to make a TV series that presumes the Civil War (and subsequent civil wars) solidified the Confederacy and here it is, 150 years later, and there are still parts of America where black people are slaves! And it’s from the two white guys who made “Game of Thrones,” so doesn’t that sound super cooool?
And people had a reaction and that reaction was NO, no that doesn’t sound so cool.
And then HBO said, well, really it’s a TV show from FOUR people, two of whom we forgot to mention in our first press release, who just happen to be black, so now does it sound cool? And people said, no, not really, and we’re still wondering why, of all the infinite alternate/dystopian/bad-news fictional scenarios to consider about the various fates of the American ideal, you would land on one that puts black people back in slavery. No matter the theme, the intent, the tone, the clarity of who is and isn’t the show’s villains, etc. (Again: Why not a show that imagines black people getting paid reparations? Or ascending to higher status and control?) (Oh, yoo-hoooo, says Amazon, which says it’s got one like that in development.)
And I think you’re reaching to compare this flap to “The Handmaid’s Tale,” which, as a work of fiction, has made its case quite strongly since the book was published 30 years ago and makes an even stronger case as an actual TV show rather than as a broadly outlined pitch that’s being touted in a press release. Also worth noting: the experiences and laws seen in “The Handmaid’s Tale,” while resonant, do not literally exist in American history, though I suppose one could argue there are whiffs of the Puritan era and other downer moments (government intrusion on reproductive rights) here and there. Slavery, on the other hand, totally existed, was totally the reason for the Civil War, and, I shouldn’t have to point out, is a much rawer wound in 2017 than most of us ever imagined it could be. I mean, look at incarceration rates for blacks. Don’t we already have a modern analog for enslavement, that we mostly ignore?
I’ve read HBO’s explanations and elaborations from the session at the TV tour. I’ve thought more about “Confederate” and what it might be like. I’ve thought about HBO’s commitment to making provocative, engaging shows and considered their excellent track record, even when series did not become the big successes the network was hoping for. After considering all this, I still think HBO ought to look for something better.
While we’re on the subject, I could do with a whole lot fewer news stories/press releases/Internet kerfuffles over shows that are IN DEVELOPMENT. I have been doing this job long enough to know that just because a network is officially interested in a show and hiring people to work it up doesn’t always mean we’re ever going to see it. I really don’t take anything seriously until I get a screener and a fixed premiere date. There are so many shows out there that have been made, premiering every week; we should have plenty to talk about without getting outraged over shows that haven’t been made.