When a kid watches and movie it can't tell the difference between the reality and the movie, whereas an adult can tell the difference. This why we have a rating system. However, when you have a reality show, there is no fiction - because what's on the TV is the reality. So even an adult can't tell the difference because there is none. When a reality show like Cops shows the danger that's all around us, person sees it as a real danger and these programs create paranoia among people.
So taking the cops show as an example tells people that there's danger all around and that we should be afraid - that's why many people become paranoiac, get guns and try to defend their homes even when there is no real danger. These kind of shows are the real danger to the society - not videogames, rock music and movie violence (unless watched by small kids who can't tell the difference between fiction and reality), but the real violence shown on the TV is perceived by people as real whereas watching a movie full of blood does no harm to a mentally developed person.
So who to blame? You have to think that through by yourself...