Hmmmmm....Brothers Grimm? Mother Goose? Dark tales from medieval forests...
Yeah, I have a book that contains their entire collection. Very dark, indeed. Hansel and Gretel, anyone?
I get what you're driving at, but think you miss the mark in at least two ways: reading to children leaves all of the visuals up to the imagination, which has its graphic content bound to the limits of the child's own experiences; they're not going to visualize anything in their head that is more graphic than what they've already seen in their lives. Also, reading to children necessarily actively involves parents who can, and should, take the opportunity to moderate the text for younger audiences and/or utilize the storyline as a springboard into discussions of motives, morals and life lessons.
In both of these ways, there can be no valid comparison between reading to a child and turning them loose with the TV.