For me at least, it is not his "thrill-seeking" that bothers me. It's his participation in a cruel activity. For example: getting seriously injured while skydiving versus getting seriously injured while beating your dog.
One thing I will agree with you on is that it's a shame he decided to partake in this, but he didn't care how the bulls and cows would fare in his quest to get his "thrills."
Oh definitely. Of course, slaughtering cows to make Big Macs is also cruel, but this is cruelty for cruelty's sake. There's nothing redeeming about it and serves no purpose.