Obviously the twist at the end is going to divide people, but I think it's important to understand why it was done. This wasn't an M Night Shyamalan twist for the sake of it.
The twist was critical to the story. Without it, there is no depth to the story.
The hidden subtext of Get Out is that white progressives carry their own brand of racism, different from white conservatives.
What’s the hidden subtext to US?
It’s that those we think of as our enemies are really just…us. They may be disaffected, they may not be as privileged, but they are still people. They are, as Adelaide’s Red Character calls her people, “Americans.” This isn’t a black vs white thing, either: Since the movie has a hilarious and riveting sequence showing the “other” versions of the family’s white friends. Anyone can be disaffected.
The point here is that there are a lot of “us” in our society that we have chosen not to see. They live in slums, sleep under cardboard, and beg for scraps. But they are us. They’re not some other people. They’re not our enemies, at least not inherently.
The message of the movie is: We shouldn’t divide ourselves into groups because we are all people. If the Adelaide character who torments the family in the movie was just another subterranean monster then the movie is just an “us” vs “them” story. Instead, a person who lived down there switched places and spent most of her life “up here.” She learned to talk, to laugh, to love. She proved that if everyone had the same chance to live as she did, everyone could be just as happy as she is.
That’s what’s so amazing about the movie: For 99% of it, you’re conditioned to think of the red-clad people as the bad guys, but the whole premise of the movie is false (on purpose). Those “bad guys” are doing bad things but the people aren’t bad, inherently; they’re bad because they were brought up that way, raised to be bitter and resentful against those who had it easy. The film’s use of the cheesy Hands Across America gimmick highlights that idea: A bunch of privileged people held hands one afternoon to “raise awareness” for underprivileged people. And after they were done holding hands, they went back to their nice homes and comfortable lives…and forgot that everyone else still had problems.
That’s a hard truth to think about, but it’s a truth nonetheless, and it's what Peele is telling us with the movie.