Humans and subhumans?? This is not a useful dichotomy. Try this instead, civilized and barbarian. And this is not a question of modern and outmoded. Killing by longrange bombardment is just as barbarian as by knife in hand.
Netanyahu has equated Hamas with the Amalekites; one of the not-top-ten commandments of God is to "Kill all Amalekites." All. The Old Testament is rife will such genocide.
The Koran has rules of warfare, but Hamas does not uphold them.
Within each civilized person is a potential barbarian. That's why we have law and public enforcement of them. People denied redress by civilized means may turn to barbaric means. So, the first order of business in a civilized society is to ensure peaceful means of redress. In the aftermath of this conflict, this needs to be given careful consideration by all concerned (essential the whole world).