Statistically rare events can assume vast symbolic significance in the narratives we forge to explain how things work. And it's hard to argue against this tendency, because statistically rare events are more psychologically salient. Not only that, but a single traumatic event has the effect that it does; it is dumb to point out that it is rare, after the fact.
Some things that seem rare actually aren't. Take, for example, presidential assassinations. Of 44 presidents, 4 have been assassinated, or one in 11. There have been many more attempts, and vastly more threats. So if we consider that in terms of homicide rates per 100,000, that is almost 10,000. So Obama is 294 times more likely to be killed than the average African American. Of course, it is hard to calculate that, because we are comparing 18th to 21st-century presidents. Let's say, though, that since Andrew Jackson, being president is physically risky job. Recent lapses by the Secret Service aren't very reassuring.