I suppose in a way you are right. If there was one crazy teacher, The other (armed) Teachers would be able to stop them. I can’t help thinking “is this what we’ve come to?”
Perhaps a better way to put this is,"Is this what we've come BACK to?"
I'd be pretty sure that nobody was expected to be defenseless,except slaves and sub-human minorities, during the first century of our republic's existence. Unilateral disarmament is a recent invention.