Nonsense. If that were true, it would be impossible for anyone to find the following account to be morally objectionable in any way:
And the LORD spake unto Moses, saying,This cannot be objected to on the ground of Judeo-Christian beliefs -- it's right there as a commandment of God in the sacred scriptures common to both faiths.
Avenge the children of Israel of the Midianites: afterward shalt thou be gathered unto thy people.
And Moses spake unto the people, saying, Arm some of yourselves unto the war, and let them go against the Midianites, and avenge the LORD of Midian.
Of every tribe a thousand, throughout all the tribes of Israel, shall ye send to the war.
So there were delivered out of the thousands of Israel, a thousand of every tribe, twelve thousand armed for war.
And Moses sent them to the war, a thousand of every tribe, them and Phinehas the son of Eleazar the priest, to the war, with the holy instruments, and the trumpets to blow in his hand.
And they warred against the Midianites, as the LORD commanded Moses; and they slew all the males.
And they slew the kings of Midian, beside the rest of them that were slain; namely, Evi, and Rekem, and Zur, and Hur, and Reba, five kings of Midian: Balaam also the son of Beor they slew with the sword.
And the children of Israel took all the women of Midian captives, and their little ones, and took the spoil of all their cattle, and all their flocks, and all their goods.
And they burnt all their cities wherein they dwelt, and all their goodly castles, with fire.
And they took all the spoil, and all the prey, both of men and of beasts.
Nor, if you are correct, can it be objected to on other grounds, since you deny that any such grounds can exist.
And yet the objection persists. Ergo, your analysis is erroneous.
But what if God used the Israelites as His instrument, using this episode in this material world to illustrate a greater spiritual truth for our benefit?
That truth is, that the wages of sin is death.
Man by nature is spiritually dead and rebellious toward God, and does not want to hear that truth, but nevertheless God has made it abundantly clear in example after example and scripture after scripture.
After all, we all die. Everyone reading this post will eventually die. Death is total in every generation. Does it seem fair or righteous to your mind that we all must die?
But we know from scripture that we are all sinners; none of us is righteous; this included the Midianites.
And God has told us, in many ways and many words, that the wages of sin is death. And the death that God has in view is not the mere physical death, but an eternal spiritual death.
Nevertheless God, for his own glory and not for the glory of man, has provided a payment for sin, a way to repair our fallen nature and give the gift of eternal life. If God has caused this event with the Midianites to be an example and means by which he has chosen to reveal once again to man the seriousness of sin, and then in turn to show His mercy on mankind, who is man to contend with God on this point?
As it is written, “Jacob I have loved, but Esau I have hated.”
What shall we say then? Is there unrighteousness with God? Certainly not!
For He says to Moses, “I will have mercy on whomever I will have mercy, and I will have compassion on whomever I will have compassion.”
So then it is not of him who wills, nor of him who runs, but of God who shows mercy.
For the Scripture says to the Pharaoh, “For this very purpose have I raised you up, that I may show My power in you, and that My name may be declared in all the earth.”
Therefore He has mercy on whom He wills, and whom He wills He hardens.
You will say to me then, “Why does He still find fault? For who has resisted His will?
But indeed, O man, who are you to reply to God?
Will the thing formed say to Him who formed it, “Why have you made me like this?”
Romans 9:13-20