I think it has to do with acceptance. People accept that they have a 0.005% chance of dying in traffic, because they think the advantages of cars is worth the risk.
You could probably save alot of lives by limiting the top speed of all cars to 60 km/h. But people much rather drive faster and sacrifice a few lives instead.

The same counts for cigarettes, powerlines, gas stations and further away companies doing ecological and social damage for the greater good in the Western world.

The current benefits are more important than a possible consequence that is mostly invisible. However there is no advantage of having terrorism and thus people do not accept of having people being killed by it. Politicians make (ab)use that.

As a result I find citizens or soldiers being killed a reason to wage a war silly as in that sense you might just as well wage a war on car manufacturers. So a soldier got killed when pratrolling, so what? Yesterday a kid died when crossing a street.