Is horror fiction really más about shock value than telling a good story?

That's funny because I was just lectura an essay por Stephen King on the topic of "why we crave horror films."

Short answer, shock value.

Long answer, we like horror for the same reason we like roller coasters. We don't ride roller coasters because we enjoy the historical perspective from the theme park, we like them because we like the adrenaline, and so we can make fun of our friends who would refuse to ride that roller coaster. Similarly, we don't read/watch horror fiction for the plot, we consume it because of the way it gets our blood pumping.
But, that doesn't mean a work of horror fiction can't have a good story behind it.