I don't want to say horror is for white people, but...
Horror movies, roller coasters, zip-lining, bungee jumping. These thrill-based activities are disproportionately enjoyed by privileged people who generally feel safe. These people are disproportionately white. People who are just trying to survive don't get much of a rush from losing power or fighting for survival, because it's everyday things.
Also, in some minority cultures, it is cathartic to watch those who are disproportionately powerful lose their power, and display their incompetence and face consequences for it. So the question follows: what is representation in a horror film? In an action or superhero film, it's saying "Yes, you too can be awesome heroic and powerful." In a horror film, it's... "You too can be an idiot, filtered into being sorted by pseudo-morality, with the exception of being a minority is no longer inherently bad enough to get you killed first." Which is certainly desirable in its own way, the permission to suck like everyone else, but is that goal understood?
There's also the little bit that most of the inspiration for the typical horror stories comes from European cultures. Serial Killers. Haunted Houses. European cultures are rich with these stories in a way that other continents are not, I think.
