You can't give all the blame for the deaths to Hamas. They gave Israel a monstrous provocation, but the decision to kill tens of thousands of civilians, and collective punishment by denial of food, water and medical care was the Israeli government's.

If party A is using a human shield, and party B decides to kill the human shield to get revenge on party A, then who is culpable for the death? I don't think it's an entirely obvious answer. I don't think anyone who can easily and automatically put all the blame on party A or B has really thought it through.

This is not revenge, this is war. Until Hamas surrenders (they haven't) they are responsible for the civilian deaths.