Is there another meaningful metric we can look at instead?
top rated and top seller. and for all three, try adding the 30 day filter.
But no matter how you look at it, "horror" is popular. Blame all the successful indie games that are horror based. As an indie developer there are many challenges and among all the possible genres and scenarios, "horror" is rather easy to implement. Puzzles are hard to come up with, so is level design and graphics. But with horror, most of the things, including the story, happens in the mind of the player. Not even a need for a complete story, you only need hints.
So this is twofold. We have developers seeing games and thinking, oh, I could make one of those.
And we have players, seeking one of those nice indie games. They do not come looking here for mainstream games. And good point with the youtubers directing people here.