Also the fact that most school shootings are done by students seeking attention. If other students who also seek attention see all that big media coverage, and the face on the shooter in every TV of the country, newspapers and the internet, they'll probably try that too.
You hit the nail on the head. But the media won't stop sharing the news with pictures of the shooter with blaring sounds and visuals of sirens. These stories are a gold mine and I think in a way many people actually enjoy seeing these kinds of stories, they're exciting and dangerous, it's a dangerous cycle.
It's the same kind of psychology that drove the Romans to the circus, but more perverse.