Canary, there are different levels of cruelty and it would be insane to pull the legs off a child because it pulled the legs off a fly. Personally, I think people who breed dogs with short legs or pushed in faces so they'll have health troubles during their lives are also cruel, but unintentionally so.
But the mindless cruelty in question here is surely well beyond normal and a fine is not going to make much impression on the pathetic individual. A stiff shift in the house for naughty people will find him at the mercy of more powerful people, many of who, I dare say, would not take lightly to what he has done. See how he likes to be on the bottom of the heap for a change.