It depends on what you are talking about. If you are refering to things such as violent movies or video games, then - Most people can decern reality and fantasy. People who watch and enjoy horror movies are games are not sadists. They know it is fake and do not enjoy seeing real life sitiuations of violence happen to other people or them. If you have such a huge problem with it, then the ratings are there for a reason. Personally, I know it best to expose your children to these things early. I've been watching horror movies since I was six. I am now 17 and I am a pacifist. I love violent video games and horror movies though. I know its not real. I haven't seen a scary movie that actually scared me, unless if your talking about "jump" scares, like the ones you see on YouTube.
Its odd. Just a part of us. Consider gladiator arenas, or how a family would all hop in their horse drawn wagon and leave early in the morning so they could get to town in time to see some dude get hung in the square. I dont think its a new behavior, it just manifests differently now than it did in other periods of time. It must be a way of making peace with one's own life(?)or unavoidable death... like a 'there but by the grace of god go I" kind of thing. Or "better him than me."
Im getting my fix from the old samurai flicks. and kung fu movies.