What crime deserves punishment by way of divinely-ordered slaughtering infants and children, donkeys and horses?
You are avoiding this from the get-go. Why is that? Is it because you yourself have failed to reconcile with the said verse? Do tell!
The reason for killing all is given in verse two, which you have been consistently ignoring. But this was the incident to which they were referring.
The only way to blot out the memory of Amalek from under heaven was to kill them all. Otherwise they would just rise up and do it again.
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Exodus 17: 8 The Amalekites came and attacked the Israelites at Rephidim. 9 Moses said to Joshua, “Choose some of our men and go out to fight the Amalekites. Tomorrow I will stand on top of the hill with the staff of God in my hands.”
10 So Joshua fought the Amalekites as Moses had ordered, and Moses, Aaron and Hur went to the top of the hill. 11 As long as Moses held up his hands, the Israelites were winning, but whenever he lowered his hands, the Amalekites were winning. 12 When Moses’ hands grew tired, they took a stone and put it under him and he sat on it. Aaron and Hur held his hands up—one on one side, one on the other—so that his hands remained steady till sunset. 13 So Joshua overcame the Amalekite army with the sword.
14 Then the LORD said to Moses, “Write this on a scroll as something to be remembered and make sure that Joshua hears it, because I will completely blot out the memory of Amalek from under heaven.”
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Your turn. Explain the ritual human sacrifice of children in Hinduism for so long without even the reason of capitol punishment, but just the lousy excuse of satisfying the blood lust of some demon.