Modern society provides us very safe infrastructure. No one loses arms or legs simply by walking down the street anymore, unfortunately. As a result people have developed a distorted sense of danger. We're squeamish and grossed out by silly things, which in many cases are simply part of life, e.g. childbirth, old age, etc, stuff that before the industrial revolution didn't even make people blink.
I suspect Marina Abramovic and similar artists of the 1970's were challenging audiences to confront these distorted fears, getting us to think clearly about what it means to be a human being. At least that's what I get out of watching these performances. Artists crawl naked across broken glass, and stand in front of a fully cocked bow and arrow. It's hard to watch, but ultimately leaves me with a healthier, and more accurate perspective on the limits of the human body, danger, and our vulnerability in this world.
I think this is why Jackass premiered at the Museum of Modern Art. Perhaps it was thought that the film accomplished something similar.
Then there are shows like Tosh.0 that could be seen in this same light, but I think that would be a mistake. Tosh.0 does the opposite. It reaffirms our hypersensitive gag reflex. He uses freakish examples of grotesque injury, and masochism that are so out of the ordinary, they belong more in the realm of our distorted and inaccurate fear of the world. I don't walk away from episodes enlightened, just even more warped than before.