I wish that my pacifist friends were right. I wish we could educate people to beat their swords into plowshares. I wish everyone was as civilized as my pacifist friends.
Violence is learned behavior. The aggressor in a violent confrontation has already acquainted himself enough with violence to believe he can successfully engage his target. The target can counter with violence provided she has the training, experience, and tools of violence.
People better acquainted with violence than I have opined here and here they make a convincing case that violence DOES solve something: namely it can effectively thwart a violent attack.
Every so often some madman steals a gun and runs amok shooting up some gun-free zone or another. These stories become tragedies when the victims respond in a pacifist fashion. But teachers need not be packing heat to thwart such an attack. They need to recognize the reality of human evil and be prepared to respond with violence to thwart it. However, this is another form of education in violence.
The strong emotions about rape or school shootings arise because these events falsify pacifist wish-dreams.