What better way to create a positive learning environment where students feel safe than by giving their teacher a gun?

Guns have no places in schools. Even if a disturbed kid comes in with a gun, that doesn't make it right for the teachers to have a gun. The proliferation of guns isn't a good solution to the problem, i.e. mental illness and antisocial behaviour. To make any headway in the issue, you need to be addressing those problems.