God judges men from the inside out; men judge men from the outside in. Perhaps to God, an extreme mental patient is doing quite well in going a month without murder, for he fought his chemical imbalance and succeeded; oppositely, perhaps the healthy, able and stable man who has never murdered in his life yet went a lifetime consciously, willingly never loving anyone but himself may then be subject to harsher judgment than the extreme mental patient. It might be so that God will stand for the weak and question the strong.
So whom does God wrong in commanding the destruction of the Canaanites? Not the Canaanite adults, for they were corrupt and deserving of judgment. Not the children, for they inherit eternal life. So who is wronged? Ironically, I think the most difficult part of this whole debate is the apparent wrong done to the Israeli soldiers themselves. Can you imagine what it would be like to have to break into some house and kill a terrified woman and her children? The brutalising effect on these Israeli soldiers is disturbing.
I find something repulsive about the idea of vicarious redemption. I would not throw my numberless sins onto a scapegoat and expect them to pass from me; we rightly sneer at the barbaric societies that practice this unpleasantness in its literal form. There's no moral value in the vicarious gesture anyway. As Thomas Paine pointed out, you may if you wish take on a another man's debt, or even to take his place in prison. That would be self-sacrificing. But you may not assume his actual crimes as if they were your own; for one thing you did not commit them and might have died rather than do so; for another this impossible action would rob him of individual responsibility. So the whole apparatus of absolution and forgiveness strikes me as positively immoral, while the concept of revealed truth degrades the concept of free intelligence by purportedly relieving us of the hard task of working out the ethical principles for ourselves.