Those deaths are on Hamas, not Israel. Israel has a duty to end the threat that slaughtered their people. Hamas hiding behind children isn't Israel's responsibility. They have no duty to Palestinians. The people in Palestine should kill Hamas and sympathizers if they really disagree with them so much. You don't get to stand by while your people amass weapons and attack another country then cry genocide when that country responds.
The responsibility lies solely with those who attacked and continue to attack Israel; those who refuse surrender and support Hamas.