Columbine HS was no exception. This extreme division within the school fed the alienation of the trenchcoat mafia. It also fed the mafia's desire for revenge. The ready availability of guns and the ready availability of how to build bombs from the Internet. This must be a part of the analysis of the situation.
Movies glamorize violence and mayhem.
A steady diet of revenge violence does also play a role in understanding what influenced Harris and Klebod. The role of parents. But there are some curious questions. The bombs were built in the family garage. The boys were deep into Goth and Naziism.