The only way that the above points could be valid is if that's exactly what you did.

Have you even been in combat or in a situation where someone is trying to kill you? The above points are totally valid. Regardless of the scenario you come up with you are asking someone to effectively operate a weapon against a hostile asssialant. It’s not a shooting range with a paper target at the other end.

I agree with you to an extent about psychological deterrence but this seems a band aid solution that doesn’t address the deeeper issue. The issue I have with this whole issue is that this shouldn’t be a problem for teachers to solve. When the system is so broken that you have to give your kids teacher a gun to keep them safe, you got a big problem.