If so he must have skipped the verse where God said, "Whoever sheds the blood of man, by man shall his blood be shed."
That quote is relevant but so is the context. First, it predates Mosaic Law by centuries. Second, it was a command given by God immediately after He destroyed the earth by water.
I.e.: the sinfulness of mankind had reached such a level that God destroyed all but Noah and his immediate family. After bringing the survivors out of the Ark, and in preparation for the Covenant of the Rainbow, God issued His command that whoever shed blood, by man’s hand his blood should be shed.
Should we not take the command of God seriously in the immediate aftermath of the destruction of all but eight souls?