Earlier quoted context omitted.
A solution narrowly focussed on school shootings (changes to how schools are constructed, changing policing in schools, etc.) is bad for that reason. OTOH, school shootings as a vivid call for action on policy that address the drivers of firearms injuries (generally or among children specifically) — currently the leading cause of death in children in the US — do not become less valid because school shootings are them…
I'm having trouble parsing your second paragraph. Are you saying that the #1 cause of firearm related deaths for children in the US are school shootings? Can you share a source?
No, I am saying that school shootings, which are themselves a small share of deaths of children, are the high visibility tip of the iceberg on deaths of children by firearms injuries, which is the leading cause of death of children.