Then you do not know Rinzai roshi (Lin Chi), who mostly used force to awaken his disciples.
Anyway, it is a Zen story, and as such it is paradoxical, full of contradictions that defy logic and common sense.
A real experience -- without words -- for sure.
Doesn't make sense though. Physical violence (other than self-defense) is something I don't accept. Force against disciples or even against (own?) children is a guaranteed way to sink in my perception to a very low level.
These ancient chinese stories date back more than a thousand years: you cannot judge them by today's standards and sensibilities. A blow given out of compassion and without anger can have extraordinary positive effects. It is not comparable to today's violence by ordinary people driven by selfishness.