You insist on your version of cause and effect. I would answer your question (What are your suggestions of how to curb mass shootings at schools or public places?) as JFK had wanted to do.
View: https://www.youtube.com/watch?v=CVDGkUIBn2A
I like the Rand Paul video. As he says if you are owning a gun to defend yourself you are not infringing on my right to life. But if you then plan to shoot others you are now infringing on their right to life. You seem to believe that all these shootings are CIA directed. You've lost me there I'm afraid. I believe there is an issue with troubled young men made sick by our society, school system and medical system who then cause carnage. I hope its never you or your family that are caught up in these shootings. Because with the current system for sure there is more coming.