Why the theatrical performances though? Not all teachers went in for this, some had such a fearsome reputation they didn’t need to. But for some it was a deliberate tactic. It combined some elements of ‘pour encourager les autres’. In the mid 18th century British Navy they publicly shot the odd Admiral to ‘encourage’ the other Admirals to toe the line and get stuck into battles when required. In mid 20th century classrooms they whacked rather more than the odd child to ‘encourage’ the other children to do pretty much the same thing – behave themselves. To this end the victim had to be seen to be subjected to discomfort and/or humiliation, usually both. And the message was ‘behave yourself, or this will happen to you’!
But there was often another element, playing to the gallery.
