It's statistically unlikely that you'll be the victim of gang violence, but does that mean it's irrational prosecute and punish gang members? No, because the activity threatens social stability vastly out of proportion with the probability of any given person being victim to it. In general, we punish crimes not because it's likely that we'll be the victims of one, but because if we don't the problem might grow out of hand and undermine civil order.
Really now. I don't need to go much beyond the evening news to know that people spend a lot of time being afraid of things that aren't likely to happen. (What don't you know about your toothbrush that could kill you? Probably very little.)
Your model of humanity is one that's much more rational and thoughtful than what I've come to expect from my neighbors. Nobody is scared of a decline in social stability; they're scared of getting shot or robbed or blown up. Usually by people who look different than they do.
I don't think anyone is making the argument that there should be no justice. Prosecuting the criminals who commit murder for the purpose of terrorism is clearly a "no reasonable person could disagree" sort of a thing.
But the question remains, how is justice won? In theory we could impose martial law and suspend elections, or permanently shut all the roads and trains and prohibit gatherings of more than five people in the same place, or nuke the entire middle east. Perhaps doing those things could bring justice to more terrorists.
Well before we reach that point, we come to a line we should not cross. We come to a choice that will cost us more of our humanity than it gains us in justice. And whipping the public into a frenzy is how popular support for crossing the line we should not cross is manufactured.
That's why people care about "justice" for murderers even though more people are killed by auto accidents. Murder upsets the social order. A car accident doesn't.
Fear of setting a bad precedent which could lead to the undermining of civil order seems to be a more complex feeling than that of being the victim of an attack. It's been my experience that the most common fears of an individual are related to sudden/unexpected pain and/or death, not concern for the social good.
And if people are truly concerned over the long term social effects of a threat, why does this not also apply to large percentages of the population routinely dying of preventable causes? Surely this is just as relevant to the well-being of society.
heart disease: "But I eat healthily ... usually"
traffic accidents: "I'm a good driver! I won't get in an accident."
It's a combination of poor risk assessment and Dunning-Kruger mischaracterization's of one's skills. I'm sure there's more to it than that.
People are terrible at estimating risk.
Before I could turn up at the airport 10 minutes before my plane took off and go the the gate and check in.
After 9/11 I was in a queue for ages and had to arrive really early. So it was quicker to just drive.
 - http://reason.com/archives/2006/08/11/dont-be-terrorized
I would disagree. My experience is that people view dying in a terrorist act as an especially horrific way to die and hence especially scary. I have had this specific conversation with people where they say it would be much worse to die in a terrorist attack than to die in a car accident.
To me it doesn't make sense. They both kill you but a lot of people see it differently.
What precedent? Isn't the whole purpose of terrorism to provoke a response -- to force a change?