That is the Beauty of Jackass
Everything is self-inflicted, unless they inflict damage on each other. True, there are parts where they fuck with the public, but they never hurt them or pay them to kick each other in the face because they have no other way of making money because they are homeless and are crazy. Those guys (that produce the Bum Fights) are a bunch of pieces of shit riding on the coat tails of Jackass, but will never amount to anything because jackass is good-natured, roughhouse fun between friends (with the occasional hoodwink of the public), and Bum Fights is a terrible exploitaion of some tragically troubles people for "fun" and profit. I have only seen clips on a TV show (actually while working out at a convention!) and just from that little bit of exposure, I too was ashamed to be human, which I usually am anyway, but this was so bad...
PS Me wannee tanks!!!!