I wouldn't want Us to be a haunted house. The movie is a psychological thriller with an important abstract message. Yes, it is about racism. I explain how it is about racism below, but please don't read it if you don't want to ruin the movie before you have seen it.
The movie is about redlining. That is why the doppelgangers are dressed in red and they form a line across the country. Redlining is the denying of services to certain populations. The doppelgangers also live below the surface, implying they are treated as inferior. They are able to leave whenever they want but choose to stay there. The rabbits are also about them going insane down below. The Hands across the America was an organization to unify different populations by solving hunger and poverty and plays an important part of the movie. There is so much more to it then that.
The movie is amazing and too important to be a haunted maze.