This is why Mayor David Dinkins and his police commissioners, including Ray Kelly, originally opposed giving cops semiautomatic weapons. In 1993, when they gave in, they put a 10-round limit on the clips. A year later, Mayor Rudy Giuliani and his commissioner lifted the cap. They argued that cops shouldn't be outgunned and would handle the weapons responsibly. It's the same argument the National Rifle Association makes for the freedom to use firearms: Guns don't kill people; people kill people.
Contagious shooting blows that argument away. If cops fire reflexively, there's no moral difference between people and guns. They're both machines, and based on recent shootings, we should limit clips or firing speed to control their damage. No responsibility, no freedom.
Alternatively, we could reassert that police are free agents, to be trusted with weapons and held responsible—not excused with mechanical metaphors—when they abuse them. You can't have it both ways.