I saw a news story on it awhile back. The problem is the nature of some of the "stunts" cheerleaders do these days. People are on top of pyramids that "don't work out" and being "thrown around", so the concerns are horrible injuries (spinal cord, head trauma, and even death).
My thinking is if they made it a sport it wouldn't be "cheerleading" any more. :) They'd have to find people to cheer on the cheerleaders. In all serious, I think there should be a set limits on the kind of performances young cheerleaders do. If they toned down some of the "height issues" (and potential to fall with the force they can fall) it wouldn't be any more dangerous than anything else. In view of what cheerleading is, I don't see any need for introducing higher risk than necessary for young cheerleaders. Some risks are necessary in life or in certain work that someone who is fully adult chooses for himself.
To me, for young people to risk possibly spending the rest of their life paralyzed or with debilitating brain injury over cheerleading is an unnecessary risk. Young people tend to choose to do things, thinking, "It won't/can't happen to me." That's what makes them fearless and so sure whatever they want to do won't end badly. What I think needs to be done is some adults/authorities to set those limits on the types of performances young cheerleaders do. People can choose to take whatever risks they want once they're beyond a certain age, but school activities shouldn't involved being cavalier about risking serious injury or death.