As someone who has been involved with the horse industry for thirty-four years, I agree compleatly with Jones. If you watch the video, I don't think he could have pulled her up, if he tried.If she had given any indication she was in distress, he would have gotten off of her. A horse with a broken leg will go down, and may take the rider and other horses in the field with them. If she dove in the rail, it could have been far more catastrophic.
She isn't stumbling or giving any indication of being in pain, while in the race.
Horses are delicate creatures. It dosen't take much for them to criticaly injure themselves. They can do it in a split second.
I saw the trainer's interview, and what he says is true. Horse will frequently injure themselves while running in pastures, with no aid from humans at all.
Most people don't know how often this happens, because they are only exposed to horse racing for a few major races. If you were at the track, or in large animal practice, you would know that critical injuries often occur. Horse racing hasn't changed much.
Do I wish race and show horse were started later, after their bodies were mature, yes. Is it finacially feasible for breeder and trainers to wait, no.