In the CBC article Illinois university shooting over in seconds: police there’s a very interesting sentence near the end:
It’s the fourth shooting at an American school in a week.
Yes, that’s right, there were three other shootings on US campuses this past week! I hadn’t heard of them. Maybe I’m just being pessimistic, or maybe there really is a problem when students getting shot in school isn’t automatically news and has to attain a certain threshold before it gets reported.