“they’ll learn from it” is not in general a good reason for doing things that hurt people in whatever sense.
“They’ll learn from it” is most definitely a good reason for doing things that hurt people in the specific case of people trying to hurt you (and learning not to). That is why I specified zero-sum games above.
“They’ll learn from it” is most definitely a good reason for doing things that hurt people in the specific case of people trying to hurt you (and learning not to). That is why I specified zero-sum games above.