This is extremely misleading. The source data is the problem here, no account is taken about what constitutes a "school shooting". For example, if someone parks in a school parking lot at midnight and discharges a weapon, that is counted as a "school shooting" because it's on school grounds. In reality it's not what anyone considers to be a school shooting, and none of the school children are affected.

Lots of shootings happen in the parking lot at high school football games, one woman got shot outside an early learning center in a domestic dispute and that too is included as a "school shooting". There are many other incidents like these which are not what we know as "school shootings" but are included in some school shooting data sites.

The problem is serious enough and there is no need to add hype to it by using poor source data. All you do is create the opportunity for counter-arguments that have nothing to do with the actual issues.