Umm ok I didn't see a link, but was this by any chance in TX in the panhandle? If so I know the one you're talking about. And lets just say a good friend picks up at that one for the big horses and has said himself, that it's the stupidest, most irresponsible thing they could do. Do I know people that go to it? yep, do I agree with it? nope. Do i disagree with ALL bronc riding? Nope.
I don't agree with the mini one because 1) there is no safe way to pick these kids up off these horses like there is with regular horses. 2) they don't gauge the kids size vs the horses, I've been told big old kids draw little actual minis and not Shetland sized horses, thus making it even more dangerous because the weight of the kid can very easily and has, pulled the horse over on top of the kid. Basically, it's nothing more than a bunch of people wanting their kids to get a start out young and wanting their kids to 'prove' themselves. It's stupid, and dangerous and they are gonna get a kid hurt bad one day at it.
That said regular bronc riding isn't cruel. My husband grew up riding them in HS and college. It doesn't hurt the horse, the flank strap is there to just apply slight pressure. If it's too tight, the horse won't buck, that's a proven fact. These horses buck because they love to do so and have been bred to do so. If they are having an off day or whatnot, they just won't buck, simple as that. They are also cared for and such by their owners as much as any of our mini's or regular sized saddle horses are.