No one is questioning if there is a problem. The question is how to solve it, which you apparently are clueless about. However, speaking of lazy, did you actually look through the list. I saw one case in the past 20 years where a student under 10 intentionally shot another student.Really? Laziness doesn't suit you well.
List of school shootings in the United States - Wikipedia
Is that enough to prove that there's a problem? How many parent of the deceased kids wished that the police would have stopped it? Are you willing to meet with them and explain that because your feelings towards cops are bad, that they should allow their kid to die.
Additionally, in the only case involving someone under 10, the individual had been involved in far more than drawing violent pictures. There should have been non-violent intervention by social workers long before it ever escalated to shooting. The problem is we are much more willing as a country to fund prisons than we are to fund social welfare programs.
So now that you hopefully have a little more awareness, do you think it is worth traumatizing every single child that draws a violent picture to prevent something that has happened once in the past 20 years?