The number of students is not the problem. My high-school graduating class alone had 1,100 students. It produced no mass murderers. Nevertheless, we can't let the government's schools off the hook. They are impersonal institutions that at best bore students by treating them as interchangeable.
Students have no choice but to be there and to do as they are told.
That kind of treatment can, given other conditions, prompt a frustrated young man to decide to lash out in a twisted attempt to assert himself. Some kids don't want to be in school and don't belong there. They shouldn't have to go. It's ironic that a few years before Littleton, a Colorado state legislator tried to abolish compulsory attendance. Maybe if he had succeeded, the 13 victims and two gunmen would be alive today.