Games don't need to have jumpscares to be considered horror games! And sometimes, jumpscares are just cheesy, anyway. Or in Slenderman, where you're just walking around and BOOM! There's Slenderman just standing there.
BOOM! One comes out of nowhere for a jumpscare. Like in Five Nights at Freddie's, where the evil animatronic robots are roving about and you have to keep track of them via surveillance cameras scattered about. They are nothing but cheap and awful jumpscares just for the sake of being jumpscares. This is why I have no respect for games like Five Nights at Freddie's and Slenderman. As a matter of fact, they're not even scary! Even if you place a cute, cuddly kitten or puppy, and use that as a jumpscare, people will still be scared because, well, it came out of nowhere. They are pointless, shock values that literally appear out of nowhere to scare the daylights out of you.