Yes, some of these have turned out to be acts of terrorism (which exists in many forms), but far more are people are simply labeled as "disgruntled", "troubled" or "bitter". Whether they live or die seems almost irrelevant because our world has opened up a stage of media exposure which is perhaps fueling the idea "why do alone what you can do in front of millions"?
Too many people are too close to the edge. Things are going to get worse, not better. Parents.....you need to look at what you are raising and society needs to wake up to the cracks in our world. Nothing will change until more lives are lost and more violence happens.....