If he took it legally, what's the issue? Not my idea of hunting, but I understand the need for managing these critters and hunting with dogs is the most efficient and effective method.
...If I saw a bunch of dogs tree a cat, I'd shoot the dogs.
Hunting over bait is unethical IMOHO. I'm a spot and stalk guy... If I saw a bunch of dogs tree a cat, I'd shoot the dogs.