TB horseracing has several issues. The biggest problem IMO is the poor breeding practices. Racing Thoroughbreds have been bred for speed for so long now that their bone, joints, and feet are only marginal at best to handle their weight and the stress they are subjected to. This is no secret, and there is no need to hide it under the rug. Horses like Big Brown (and I just use him as an example as he is well known) that are genetically unsound should never be used as breeding stock. But he was fast, and he is. As a former breeder for many years, I consider that irresponsbile breeding. Money talks, though, and so the poor breeding practices continue.
Under public pressure and in light of declining attendance and revenues, the JC has caved and has made quite a few changes to make racing safer. No discipline is perfectly safe, but there have been some large strides made in the TB racing industry in recent years.
Despite the rhetoric from the industry and the "studies" they tout, I still don't accept that juvenile racing is prudent, but I don't see that changing in the near future.
There are few spectator sports more exciting than horse racing. I have been a fan all my life, and have had the pleasure of seeing some great horses, including Secretariat at the Preakness, Smarty Jones at the Arkansas and Kentucky Derbies, and many others. However I find it very sad that greed has trumped prudence and soundness in the breed has become such a serious issue. There is an inherent danger in overspecialization when it is at the expense of soundness, and I find the theory of breeding and nursing a horse through 3 years of racing and quickly retiring it to stud before it breaks down to be a poor practice.
In summary, much has been done to improve safety, but until owners and breeders began reintroducing soundness and hardiness and stop the insanity of breeding horses with extensive family histories of physical problems, there will be a cloud over the industry. I find that that very sad...