Considering the fact that the US has far, far more mass shootings at schools than any other developed nation (most have zero), I'd say the liberals aren't paranoid. They're just watching the news and have pesky souls that make them sad when a child is senselessly, preventably murdered.

I'd say that the dramatic overreactions of zero-tolerance policies in the wake of school shooting have less to do with liberalism or conservatism, and much, much more to do with bureaucratic cover-your-ass-ism, because if you DIDN'T ban nerf guns, what happens when a kid brings a gun disguised as a nerf gun to school?

Certainly the zero-tolerance policy of this and other districts cannot be effective, and certainly they aren't preventing any school shootings -- zero tolerance policies reached their apex in the years after columbine, but there are still shootings on a regular basis. So a liberal that pushes a zero-tolerance policy is certainly not doing it from the rational, evidence-based center of their kind soul.