Planning ahead and practicing is what these teachers say now gives them the confidence to wage war against an attacker if they have no other choice.
I once read that the Chinese leaders back in the 1800's gave confidence training to some troops making them think they could realistically defend themselves against other nationalities who were coming into China with firearms. They didn't do this because they were anti gun, the leaders didn't have enough guns to give to all their soldiers. Some of the few guns they did have in practice sessions were not loaded with lead, to suggest to the troops that they cold survive getting shot if they charged toward the enemy. The training gave the Chinese a lot of confidence. All it did in real life however was get a lot of Chinese killed.
Susanne Gratia Hupp and her father were in a mass shooting. The father felt like he had to do something to stop the slaughter, and charged toward the killer. All it did was get him killed. Meanwhile his daughters handgun is in her car, because it was against the law to have it with her. She had a clear close range shot to the killers back, but she couldn't take it, simply because she was a law abiding citizen and the killer wasn't.
I don't think there's anything wrong with it, as it does work sometimes, and is better than merely standing there and getting shot like a sheep. I think however it should be
a complement to and not
a substitute for something which has been proven to be more effective against a mass shooter.