Why does God pass off responsibility of law enforcement to man (Gen 9:5)?

God personally punished the first crimes, much as he gave the first devastating punishment to all mankind in the Flood, and for that matter, much as he destroyed Nadab and Abihu as examples to future careless priests. Notice in every case that God is incredibly strict (on which, see below). What is interesting in every case is that, while God initially is the law enforcer, in time he passes the responsibility to man. So—why? To begin with, in each case when God passes off responsibility to enforce law, he specifically deputizes man, though only properly righteous and consecrated man. In this way, he appears to be training man to be fellow judges and executioners with him. Now, as to why he does not simply continue in this original role, it is probably not as if the role were beneath him; rather, this is a rite of passage as man leaves his nonage. As man is created in the image of God, more righteous or godly sort of men (if that is permitted to say) ought to be able to serve as judges over other men. God is building his church and the inhabitants of the future kingdom of God. After being placed in authority over Israel by Yahweh, Moses specifically deputizes literal judges over Israel (see Ex 18). Future men will be made, explicitly, judges of a much holier kingdom, of the twelve tribes of Israel in the Kingdom of God—as Jesus says of the twelve apostles. “And I appoint unto you a kingdom, as my Father hath appointed unto me; that ye may eat and drink at my table in my kingdom, and sit on thrones judging the twelve tribes of Israel.” (Luke 22:29-30) Practice would seem to be in order.