He was trying to get us to quit hitting the drum too hard. The whole point was to illustrate what happens when you bang too hard with the drumsticks. IOW, he wanted us to learn to hit the drum no harder than we would hit our head.
I thought it was a great illustration and although I never really got very good at playing the drums, this one little exercise certainly improved what little technique I had.
The thought of my daddy suing the school over this sends me into hysterical laughing.
BTW--whis was in the 40's.
Full disclosure: both my parents are educators and are disgusted with 90% of their "professional" colleagues.
Over reaction.