If one accepts the right of Israel to "defend" itself by making general attacks against the Palestinian population, then one accepts the inevitability of civilian casualties. The problem of defending against irregular militia that strike from among the civilians population is not a new one. In fact, the Jews fighting to make Israel in the late 1940's used this technique quite a lot. Every "underground" uses this strategy against an occpying army. It is not common to see tactics such as those used by Israel in reponse to this activity. The Nazis famously wiped out an entire Czech village because they sheltered the assassains of a prominent Nazi. The usual response to what we now call "terrorist attacks" was to develop intelligence of their organization and go after the leaders and arrest them. Widespread killing of civilians does not produce the desired results. The idea is, if the occupiers are going to attack the civilian populace at every opportunity, then the only option for the civilians is to support the "terrorists" as the lesser of two evils.
Suspect Bangkok bomber arrested, found with possible bomb-making materials (Reuters)
from the article: Goldstone has paved the path for a second Gaza war