This definitely wasn't a reasonable action by a school.
All I can think of every time a lame incident like comes up is how fortunate (lucky) I was compared to kids today that I attended the schools I did, when I did. Us students back then had a blast and interacted with respect and admiration for our teachers, some even becoming long time friends into our adulthood. The teachers during my school years even into college did not ram their "personal" agenda's down our throats, they taught students, they encouraged students, like teachers are suppose to.