As I said before, by that logic all parental discipline sends the message that if you are bigger than someone else, it is OK to enforce your will on them. Whether the method is physical pain or emotional pain, the message remains. Should parents never discipline then?
The conclusion doesn't follow. Nothing about disciplining with emotional or other non-physical methods requires owning greater physical force. Beating does. If you weren't bigger/stronger than the other person, you couldn't beat him because he'll beat you back.
More, I'm pretty sure the 4 year old I nanny is not coming to that sort of conclusion based on the very occasional swat to the behind. I believe it's likely that, at least until very recently perhaps, most children were spanked at some point. It's just a common form of parental discipline in this country. Did those children all grow up believing that it is ok to cause physical pain if you are bigger than someone?
Obviously, that's the message. Just look around -- we're a society swimming in violence. Some of us get past that message, others still struggle with it. Some never reconcile.
It might be better if such a message wasn't propagated in the first place. This could be step one.
As for "common", hey it used to be common to bleed people with illnesses too. George Washington died from it. Sometimes we humans have to stop and take stock of what's "always been done this way" and decide, "this is fucked up".