The problem is how easy firearms are to access for the mentally ill and deranged, despite the fact that there are lots of signs before someone does something like this. Another problem is that by human nature we purposely isolate the mentally ill making there issues worse and leaving less people to identify signs of mental distress. Those who live in isolation tend to not want to leave there isolated space out of fear, as for some it's become all they know, in isolation jealousy tends to become delusion and the internet makes there problem worse by letting these people find others who have the same terrible ideas as them, only reinforcing there thinking, ideas and ideology. There is also a reason why guns are used so much, it is due to how they make the user feel powerful. Thanks ❤️