Many media commentators reflexively described the Navy Yard shooting in Washington, DC as a "tragedy." This designation amounts to a sloppy, misleading abuse of language. September 11th wasn't a tragedy, nor was the Holocaust; these were crimes, the product of evil intent and willful choice.
Natural disasters like earthquakes or epidemics that kill millions count as tragedies, because the suffering resulted from no wicked purpose. Occasionally, major wars (like the Civil War) can also qualify as tragic, when soldiers on both sides serve through a sense of duty, not vicious bloodlust. But when a killer, or a group of killers, decides to murder innocents out of sheer love of violence or demented ideology, moral clarity requires denunciation as a conscious — and evil — crime.
That crime may have tragic elements, but the guilt of perpetrators shouldn't be ignored or dismissed.