Amoklauf in the Netherlands

In a shopping mall near Amsterdam, a gun-club member apparently intent on death has taken at least six people with him. As I write, police are searching nearby shopping malls for bombs the killer claimed to have planted. His motive for suicide remains unclear to the general public. This is the part where I probably should say that not all gun enthusiasts, especially outside the U.S., are "gun nuts," though the shooter, who apparently had a legal wrangle over an alleged illegal firearm, might well merit the label. But while it is objectively true that not all gun collectors or hobbyists are "nuts" in the American sense of the term, it is also objectively true that any concentration of collectors or enthusiasts in an area makes an amoklauf more likely. Does that mean there shouldn't be gun clubs? I wouldn't go that far, but any such club should feel some responsibility to monitor its members more closely. I don't know if the shooter's club was dedicated to the history or craftsmanship of firearms, but distinctions should be drawn between presumably innocent reasons for collecting guns and more questionable motives. While I doubt his club membership had anything to do with the shooter's suicide run, we might wonder, and investigators will ask, whether other members noted anything worrisome about the man, and whether any kind of bias related to their common enthusiasm led them to give him a benefit of the doubt that has proven unwarranted. Let's put it this way: if some people believe that Muslims ought to monitor their own mosques for signs of "radicalism" that might result in violence, shouldn't they request the same of organizations whose ownership of or access to weapons is not in doubt.