Just as it's not a smart thing to joke about bombs when at an airport, students should keep in mind that blowing off steam by joking about shooting a teacher is not smart in today's environment.
The intent of the student is not really a viable factor our world of today which includes actual deadly school shootings.

And it's fine to rail against restrictions on freedom based on today's PC campaigns, there have actually been lives lost in schools.

This is one of those times when our values are beset by internal contradictions. If the song had been whispered between two boys clad in black coats, and followed a day later by a shooting, would you be worried about PC rules or would you be complaining that warning signs had been ignored? It gets complicated, eh?

~Susan