I suppose I'm conflating school shootings with mass shootings which is what most people worry about, a la Columbine or Parkland. The figures in your link are mostly gang violence, which is a completely separate although valid issue.

We do absolutely have higher rates of targeted gang violence than other countries, which after controlling for factors like density and poverty is highly correlated to young urban male demographics that aren't as prevalent in other developed nations. There is no single policy that can solve the numerous social and systemic failures that generate this problem, but due to the nature of these vendettas they would assuredly be carried out with knives and shanks in the absence of guns.

The figures in the article are literally school shootings, i.e. shootings on school grounds.

Maybe you should reread the comment you are responding to in order to understand why your objection is meaningless in the context of the discussion.

All mass shootings in schools are school shootings, but not all school shootings are mass shootings.

Why is the distinction important? We don't want school shootings, regardless of whether one or more people die in them.