They always are, and the question becomes what can we (if anything) do about it to try and prevent such senseless acts of violence. We don't have a particularly great mental health system here in the U.S., but I'm not convinced these types of things would go away even if we did. Just a terrible, terrible, event.
No these things will never go away. There is also no reason that they should happen with such regularity. Lots of pieces of the system need to be rethought. Not just gun control for sure. Mental health is huge.
We'll never eliminate it. History proves that, but we sure as hell can limit it better than this.