Because they're teachers, not armed guards. And if you don't think the students know who among them would and would not shoot, you're the one with stupid dreams.
That is not based on real world experience or reality at all. Where did all the elaborate government solutions only people come from on FR?
They are armed citizens.
The CHL toting couch Feis had no chance UNARMED.
I'm not a guard, not a cop...just a person...but you threaten me, my loved one's and friends. You are going to meet armed resistance.
And I know plenty of people in Hospitals, Schools, public places...that think just like me.
Just because they are a teacher, a nurse, a doctor, a cashier...doesn't mean they aren't capable of defending themselves....and others.