The shooting was relatively tame.....
The shooter only killed one person before killing himself and as sad as that was in real life lately (think virginia tech) there have been shootings where MANY people died.
Why has no film maker done a movie where they recreate one of those events, either a fictional movie inspired by real events or a recreation of those events using actors that go deep into the aftermath, you could do an entire drama movie about a school shooting and the aftermath.