You make unwarranted assumptions:
“The restriction on blood is different from the restriction on fornication, because no one is hurt by eating blood any more than by eating steak”
The restriction on eating blood was based upon life being in the blood and life belonging to God to decide its use, not man. The harm was in the violation of God’s law and the taking by man what did not belong to him. (Gen. 9 and Lev. 17)
If from that you conclude that God told the Jews not to kill animals, you are wrong. They killed them all right.