Why do I care if he cares? Do you think it less wrong to punch a granny because a person doesn't care and thinks it's reasonable?
When you feel the call to morality, you feel the call to God. Nothing less.
So if God changes his idea of morality (Infanticide is bad/Kill those Canaanite babies!) periodically, does he have to flash our moral BIOS so we know what to feel?
You are trying to make a rational argument for altruism without God and now you claim not to care if you can make an argument to the thief regarding why he should not steal. You don’t care how he feels. Some athiest Sunday school teacher you would make!
God does not change. He has changed the duties of men to him many times; from one rule in the Garden of Eden, to many rules before Christ, to a few simple rules again.
(Infanticide is bad/Kill those Canaanite babies!)'
Is infanticide ever a just act? If your answer is no, then what of the doctor in the emergency room that sacrifices the child the mother carries to save the mother's life? Since God is perfectly just, perfect justice here applied. Do you know that God didn't take those chidren immediately into Heaven?
periodically, does he have to flash our moral BIOS so we know what to feel?
Absolutely, it is called the Holy Spirit, an aspect of God.
John 16:7-14 But I tell you the truth: It is for your good that I am going away. Unless I go away, the Counselor will not come to you; but if I go, I will send him to you. {8} When he comes, he will convict the world of guilt in regard to sin and righteousness and judgment: {9} in regard to sin, because men do not believe in me; {10} in regard to righteousness, because I am going to the Father, where you can see me no longer; {11} and in regard to judgment, because the prince of this world now stands condemned. {12} "I have much more to say to you, more than you can now bear. {13} But when he, the Spirit of truth, comes, he will guide you into all truth. He will not speak on his own; he will speak only what he hears, and he will tell you what is yet to come. {14} He will bring glory to me by taking from what is mine and making it known to you.