schools is there is no barrier to entry. You don't have to be able to run at least a certain speed. You don't have to be able to jump a certain height. You don't have to be on track to take Calculus or pass the AP US History test. You don't have enough confidence in your speaking ability to join debate.
It's a great place for all sorts of people to fit in and find a niche. Some of the kids can do all those other things. Some can't. And I'm glad they have a place to fit.