Another revenge killing happened recently in Florida when a little dog brushed up against a gator. His guardian was able to rescue the little dog, and the gator took off, likely never to encounter a little dog again.
Nevertheless, a trapper went out to capture the gator, kill him, and stuff him for the man to keep as a memento.
We are happy the little dog was saved and the man was certainly heroic, but question what practical good was done by this benighted response.