Whatever.
I was raised on horror movies from the age of about seven. Not comic-book stuff like (I imagine) Blade is, either. Horror/Supernatural/Slasher stuff. Most of it at drive-ins, in the beginning. By the time I started going to theatres, I had been properly socialized to sit quietly and watch the movie. I recall seeing, between the ages of 7 and 11, Carrie, Halloween, The Omen, Piranha, Coma, The Amityville Horror, Jaws, Motel Hell, The Shining, The Fog, Silent Scream, Alien, Outland, Friday the Thirteenth, and a ton of other less memorable splatter/suspense films.
You know, it did me no harm. I was given to understand the concept of “make-believe.” I only remember one film that actually stuck with me for a bit: The Swarm. That one hit a nerve, because bees were real, my backyard was full of them, I’d been stung before, and I fully bought into the idea of huge swarms of angry bees. I think I may have heard of “Africanized” bees in real life, too-- either at school (grade 2) or on the news. I had a couple of nightmares about bees after that.
Apart from that, the only effect that a steady diet of horror movies had on me was that by the time I was thirteen or fourteen, I was thoroughly bored of horror movies, and I had to know it was a really good one before I’d watch it.
I think the idea that scary stuff is poison for children is ridiculous. The most treasured bedtime stories of the past three hundred years make Hollywood spook tales seem fluffy-bunny. “‘My mother killed me, my father picked my bones, my dear brother buried me under the marble stones.’ Good night, dear heart.”