There is a vast difference between an ox who gores a man, or for that matter a dog which maims a child, to that of a whale kept in captivity. We have a law in the UK that if a dog bites a human, especially a child, without provocation, then the dog is put down.
I also believe that if an ox or other farm animal that maims or kills a human should be put down, but not by stoning, but by being shot between the eyes, (where death is instant) or given a lethal injection, which causes the beast to die in its sleep.
The whale kept in captivity is altogether a different matter. It is totally against nature. In its natural environment it hunts in a pod, not entertain humans. The death of the trainer was a tragic accident.
I have visited Sea World in San Diego twice in 1995 and 1997. There I watched the Killer Whale perform (and got a thorough drenching while fully dressed - thank goodness it was warm that day). The drenching made me realise how unnatural the whole set up was, and left with the wish that the whale was released back to the ocean where it belongs.