Or perhaps their editors passing over such stories in favor of what sells. Emotion after all is what sells --- some nut goes on a shooting rampage = gold mine. When that subsides you re-run endless witness accounts to milk some more. Then you trot in the conspiracy theorists to stir fear and loathing. The more analytical questions of circumstantial background are not nearly so sexy. They don't sell enough papers. Well we can't have that when there's money to be milked from emotion, so "let's take you to San Francisco because -- yay -- we have another shooting we can milk". Lather, rinse, repeat ad infinitum. Such are the wages of news-for-profit.