A child that grows up without being taught to respect their parents and other adults will not learn to respect God, the laws of a civil society, themselves, or anyone else. They will believe they are the master of the universe. Violent video games, fantasy games, their ability to develop some delusional on-line persona on social media, and seeing all the attention that massacre perpetrators get may all have a role, but to me it all starts when someone is 2 - 3 years old and their parents try to negotiate with them instead of setting firm boundaries.