In Australia I know that the RSPCA will always attend the rodeos that are held to ensure the animals are treated well however I myself have never witnessed the animals being treated in a way that would warrant them being shut down completely which is what there main aim is!!
Both the horse and bulls that are used are in excellent condition' granted the horses are not in show condition but they don't have to be do they as long as they are healthy and not roughed up' which if you have ever been behind the scenes of a rodeo you may notice the horses and bulls are quite humanized and will come up for a pat at a fence! This is not the behavior of an animal that is abused and consequently un trusting of Humans!
I have a few close friends who ride the broncs and also a friend who rides bulls and have been to a few practice's with them usually held on a private property and all the animals are quite at ease and are looked after as well as most pony club horses in fact some even better as a good buck horse can be quite pricey. As long as there is a regulating body and the standard is upheld within the sport I see no reason for it to cause concern.