That's a serious question. It clearly isn't fun for them, but is it any worse than American style bullriding?
That's a case where I don't particularly enjoy watching it, and when someone gets stomped or gored I don't feel too bad for them, but I don't think the animals are (usually) harmed by it.
Same for this (maybe). I figure anyone who loses a finger to a snapper because he's trying to pull the head out of the shell was pretty much asking for it. But does it actually hurt the turtles? That's not clear from the video.
So no, I'm not asking you to track down examples. I don't care that much. It's not like I'm going to go out there and start protesting or anything.