The setting is controversial because of climate change, class warfare, and institutionalized slavery? Guess what, those are real things. You can’t have a dramatic story without conflict, and the more relatable it is the more effective the story.
Up to a point, yeah. But the point at which it switches from fantasy fun times to
too real to be fun is remarkably...
individual.
Like, if you got a player whose husband recently died, maybe skip the bereaved widow NPC you were thinkin' of including.
...and if you're playing in a setting that has Bereveaved Widows as a big part of it...well, maybe avoid that setting.
Slavery, especially, is something that for a huge part of the population of the US can make it hard to enjoy being a make-believe magic elf. Because it was a real thing whose far-reaching, traumatic effects reach forward for multiple generations and whose ugly legacy we are
still struggling with as a country. Hell, parts of it were on multiple state ballot measures in 2022, the past isn't even really past yet when it comes to that.
Also, a lot of the "primitive" vibe of Dark Sun is hugely thorny. Old colonialist ideas of what makes a "proper" civilization and all that.
Personally, I'd say if they can pull off
Dragonlance and its huge amount of land mines, they can probably pull of
Dark Sun in a way that could work. But I don't speak for everyone, and maybe they don't want to (not worth the effort, too many things could go wrong, their advisors are telling them its a Bad Idea, whatever), and that's legit, too. I do not mind the hints I'm seeing of Dark Sun being worked into other settings (some DS elements were part of Spelljammer, for instance).