This is why these random acts of mass murder provoke such anxiety and handwringing from not only journalists and politicians but also from average Americans: you cannot avoid these horrible crimes by staying out of minority neighborhoods, nor can you avoid them by staying away from dangerous acquaintances. It is very easy for most Americans to see the average, generally not well-publicized murders as an unfortunate but not terrifying situation because they are far away and affect people unlike themselves. Monstrous crimes like Newtown are terrifying even though they are quite rare, because they are unavoidable unless we deal with the root problem for most of these: deinstitutionalization of the mentally ill.
One of the great tragedies of the degradation of the academic community is how many people holding academic appointments engage in reductionistic thinking: they pick one single factor to explain a problem, and ignore other possible causes. Murder in America is not one thing; it is many things. Inner-city drug gang murders have one set of causes; random acts of mass murder have a different set of causes; revenge killings by disgruntled former employees have yet a different set of causes; domestic violence murders are again different in origin. When the mainstream media encourages reductionistic thinking by giving those who promote these single-factor explanations a platform, it makes it more difficult to have a serious discussion about complex problems. This does not serve the public interest in making good public policy.