>>715108850I'm gonna play devils advocate and say because the western horror creatures all strike at very base human fears instead of convoluted, but common in Japan, concepts and scenarios.
Ghost: fear of the regrets of the dead coming back to haunt you.
Vampire: fear of control and assault, often with sexual assault and rape undertones.
Zombies: fear of the dead and mobs- of massive, uncontrollable swathes of people that want (you) dead.
Werewolf: fear of uncontrollable transformation, of being forced against your will to commit heinous acts, or of another human secretly harboring thus unknown and dangerous trait and posing a threat to you.
Most of these boil down to two basic concepts: loss of control, and the unknown. You have to figure out who the werewolf is; what the ghost's regrets were- and you can't control the zombie horde charging at you, nor the vampire that wants your precious blood- and may enslave you after taking it.
Contrast this with "ghost that kills you after choosing toilet paper" and "spirit that freezes you to death in a snowstorm" and so on.
However... this completely Ignores all the western monsters that ARE like this! Dullahans are headless horsemen; half damned souls that can't cross water. Witches are just people with magic, unknown powers that might be a boon or a bane.
I'm sure there's some Japanese horror monsters that fit this bill- but most of the ones I can think of fall into the "do x, get fucked over" category