The informal instances were very one-sided applications of force to achieve immediate ends rather than an agreed process to terminate and rectify a recognised ongoing fault of behaviour.
It may seem odd (and it does to me) but although I can accept my own situation (and would accept the same result under exactly the same circumstances of age, society, educational practice) if the same were to have happened to one of my children in more recent times, this would be unacceptable. (This was not the case with my parents, despite never using any form of physical punishment or control at home.)