You hit dogs to stop them pooping inside? I don't think there's anything grey about that...
You speak from a moral high ground but i really think these questions are worth exploring
By rewarding correct behaviour. Those questions have already been explored, and contemporary experts pretty much agree that punishing, especially physically beating, is counterproductive. Both for dogs and humans.
I can tell you think im insensitive. I appreciate you punishing my behaviour with stern talking. Clearly even you see the benefit