Eating disorders are not a choice. It is a horrible, terrible disorder that affects the way the person thinks about both food and herself. When an 80lb girl looks in the mirror and believes she is fat and therefore "chooses" not to eat again that day--all the while berating herself that she's not good enough, and "weak" because she can't always avoid all food all day, and that people are disgusted at how fat she is............. Personal choice? Seriously?
As for the flyer, well, wanting to be a flyer may have been trigger, but cheer wasn't responsible for the disorder itself. Her trigger could just have easily have been dance or gymnastics or volleyball or a comment from a friend at a sleepover. In her mind that the time she probably wanted to blame cheer, and it was inflammatory (and therefore "good") for the show.