Horror just has to be horrifying, scary. You can do that without gore. There's a trend for gore and splatter, splatterpunk or how many other names you now have for it. None of it is necessary. You can have the creep factor, the scare factor, or just the horror factor without a drop of blood. Just the suggestion of such things is all it takes. You don't need the instant gratification which seems to be expected now from many people.

On the other hand, you can also bore a lot of readers if you don't get to the point with said suggestions or creep factor as well. Better make it damned interesting, the story better move, and stuff needs to happen or you're going to lose the reader.

I can go either way, gore or suggestion, as long as the story moves and is not too literary. Personal choice. My writing has some gore but I don't overdo it. There are gory parts, but they're not the main focus, the story is. They're just the aftereffects of the "icky bug" (monster, bad guy, entity) doing it's thing. The focus is on the good guys overcoming the obstacles and prevailing in the end. The creepiness is in discovering the icky bug exists, how the icky bug develops, discovering the first corpses, the big battle at the end, etc.

You can write a story with suggestions and threats, but never actually show any of it. Some might call it boring, while others might get scared out of their pants. It all depends on how you grab their attention and keep it until the end.