Hey, all those who think whacking your kids, or letting someone else do so is a good idea, because you are convinced it is not illegal, are you also going to beat your wife, because there are numerous sources in halacha that allowed it in certain circumstances?
Are you going to justify doing that today, too?
If you need a punching bag, go to the gym.
If you need to demonstrate power in your relationship wit your kids or with talmidim, do it with leadership, with example, with giving praise, all of which are way more effective than with fear.