I wholeheartedly agree. I have nothing but sympathy for those involved in the incident, but no Police force in the world can stop something like this from happening. One only has to look at America to see similar shootings in a country where Cops are armed to the teeth.
The Police are not mind readers and no matter what previous dealings Cumbria Police had with this individual, I'm sure they didn't see this coming.
Even when there are obvious concerns about individuals, their human rights or legal constraints can sometimes hinder positive action by Police. Sadly it wont be the last such rampage, but I'm not sure if there is any real solution.

I've not read a lot about the aftermath of this, but I was proud to hear stories of unarmed cops rushing to the scene to do what they could. Yes, it's their job and I would expect nothing less, but people forget that Police Officers are ordinary human beings that have to do extraordinary things.