Proportionate casualties is not a requirement, but targeting civilians is a war crime. The IDF has repeatedly and actively targeted civilians, even when no military targets are present in the area. They have not prosecuted the soldiers and commanders that have carried out those crimes.

This makes the entire regime culpable, and given that it is a democracy, the electorate shares a part in that culpability.

Notice that the entire polity of Palestinians is being held fully culpable for the actions of... Its unelected leadership.

... Also, using a war to displace an occupied civilian population is a genocide.