Maybe Rebbeim may love their students but that doesn’t mean the students feel the same way back or even see the love. (I had a principal whom all the teachers said truly loved every student but we never felt it, so what was the point of the love?)
But anyway, if a parent hits their kid (rarely and all) the kid automatically goes back crying to the parent. But if a teacher hits a kid, the kid could very well become resentful of the teacher, school…