Of course, killing innocent Palestinian women and children will not contribute in any way to the safety of Israeli citizens, that is true. Therefor, the IDF is not trying to kill those women and children, but to destroy houses. Hamas is using these houses as rockets arsenals, and placing the rockets launchers inside those houses. And Destroying rockets and launchers does contribute to the safety of Israeli citizens.
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And yes, by only destroying Hamas' arsenals, infrastructure and killings few of it's important members, Israel will not get peace for the long run. It will get the Israeli citizans a few years of peace, but than it will all happen all over again. Therefor, I believe a more drastic action is needed, but that is for a completely other discussion.