There is an irrational madman shooting at you and your family. So far, he's missed, because you and your family have taken concealment. You go to return fire, but the madman is using his own daughter as a human shield, and in order to shoot him, you have to shoot his daughter.
A. Do nothing but huddle behind your concealment until the shooter shoots you and/or your family through your concealment
B. Shoot him through his daughter.
C. Try to reason with the irrational madman, even though other people who've tried to reason with him have been shot at, and you've already tried it with no result.
There is only one ethical answer - B. Anything else results in the murder of people who you are supposed to defend.
As an outside observer do you blame for the daughter's death? The man who shot her in order to defend his family, or the man who used her as a human shield?
This is the situation that Israel is currently in. They can do nothing as Hamas shoots rockets at their citizens, they can try to negotiate with Hamas, or they can grit their teeth and shoot at Hamas, despite the terrorist group's willingness to hide behind human shields. Israel chose least bad of the three answers, and they cannot truly be blamed for it.