Many on here have experienced horses that were tried BL and got hurt, didn't make, or faced abuse in their past.
But think about why these people got ahold of these horses at dirt cheap prices.... Or as misrepresented horses....
In any study you can not only take the failures and conclude your findings to the whole... Yes some horses get hurt, yes some are abused.
If I was only exposed to the Thoroughbreds that were already dead put down at the track I would conclude that racing always leads to a life ending injury... When that is not the case at all.