When you get people a bit off their rocker, and they get filled with anger and hate, bad things happen. When they have access to guns, very bad things happen, and doubly with access to automatic weapons etc. Canada has the right laws mostly, i'm so thankful.
We've had a soldier hit with a car in QC, a DND recruitment centre stabbing, an ISIS supporting lady go after people in Canadian Tire with a golf club, etc. These could have been so much worse. Same with the Parliament Hill shooting, had he used something deadlier than a hunting rifle.