Disabled, queer, poor teens are not shooting up schools. The profile of a school shooter is overwhelmingly white, male and middle/upper class. A shooting is an ultimate tantrum for which the perpetrator is never held accountable.
Unfortunately, the reality is that there are often good reasons why young men who shoot up schools are excluded by their peers. If anything needs to be targeted, it's their ability to self-reflect on that and deal with (often not real but perceived) rejection and confrontation in a healthy way, but I doubt that this will go well.