"I agree with the principle to an extent. However, in the case of school shooters, I don't think it can be justified. Same with rape. There's definitely a line, but like you said, those are the most extreme cases.
On the topic of mass…"
"let he who has not sinned throw the first rock?
I should also mention that many people regard their way as "the best" way. If you do something a different way, you're shaking that belief, and they become defensive."