I think you may have a point, but the thing to remember is that there is never one particular motive behind any of these things apart from RETURN ON INVESTMENT. Everything be it human or event has an ROI that is calculated by these people. How do you get the maximum ROI from a school shooting? You choose a target with a symbolic name and throw in a fully operational MK Ultra subject as a test case. In addition you get your anti-gun lobby friends prepped for the aftermath political shitshow and phone up your friend Mr. corrupt security contractor to provide him with a new client. For good measure you also make sure the kid buys his guns from an outlet you have been trying to take down.
SEE HOW THIS WORKS?