It's about the least concern.

There's a shit ton of things that are certain dangers to my kid. Plastics, toxins, climate change, political instability, and that's just the obvious ones that increase the risks of death and illness way more than the chances of some idiot kid sourcing a gun and popping off randomly with no real skill.

And, it's the risk factor a parent can do something about, directly and immediately. Home schooling is a realistic option for now. There's other ways to bypass in person education in a pinch.

It sucks. It's a problem. It just isn't even on the radar of real, demonstrable risks.