This is not to say that physical punishment is wrong. Chosech Shivto Sonei Benoi- someone who holds back the stick form a child, hates his child. Where it’s necessary and appropriate, and of course not out of anger, it’s permissible for a parent to hit a child.
But as for a teacher, rebbe, I definitely wouldnt want a stranger hitting my child and I believe it’s very wrong. (especially in public).