Nations tend to focus far more time, money and attention on tragedies caused by human actions than on the tragedies that cause the greatest amount of human suffering or take the greatest toll in terms of lives. … In recent years, a large number of psychological experiments have found that when confronted by tragedy, people fall back on certain mental rules of thumb, or heuristics, to guide their moral reasoning. When a tragedy occurs, we instantly ask who or what caused it. When we find a human hand behind the tragedy — such as terrorists, in the case of the Mumbai attacks — something clicks in our minds that makes the tragedy seem worse than if it had been caused by an act of nature, disease or even human apathy. …
Tragedies, in other words, cause individuals and nations to behave a little like the detectives who populate television murder mystery shows: We spend nearly all our time on the victims of killers and rapists and very little on the victims of car accidents and smoking-related lung cancer. "We think harms of actions are much worse than harms of omission," said Jonathan Baron, a psychologist at the University of Pennsylvania. "We want to punish those who act and cause harm much more than those who do nothing and cause harm. We have more sympathy for the victims of acts rather than the victims of omission. If you ask how much should victims be compensated, [we feel] victims harmed through actions deserve higher compensation."
This bias should also afflict our future thinking, making us worry more about evil alien intent than unintentional catastrophe.
This bias is easily explained: we expect (in the sense of "demand") people to treat each other decently. One can't be sapient without having this duty. Thus, people close to the victim of a killer or rapist quite reasonably believe there's no excuse for the crime to have occurred -- a specific person is responsible and needs to be punished and/or made to pay restitution, so feeling outrage toward him/her is the only appropriate response.
In contrast, car wrecks (excluding those caused deliberately or by gross dereliction) are sufficiently unforseeable (and the precautions that might have prevented them are sufficiently non-worthwhile) that there is nobody to blame: such things inevitably happen to a few. The same reasoning applies to lung cancer, if we credit the victim's own decision that smoking is enjoyable enough to be worth the risk to him/her. (If we don't, then it is self-inflicted.) In either case there is no reasonable target for outrage, except maybe "God".
subsidiary to repugnancy bias and commission bias (bad things committed by an entity with apparent agency is more repugnant).