And I commanded Joshua at that time, 'Your eyes have seen all that YHWH your God has done to these two kings. So will YHWH do to all the kingdoms into which you are crossing.'
#deuteronomy 3:21
#devarim

God owns you. He owns your soul and every atom in your body. He has every right to give you life and to take it away again. That goes for every man, woman, and child who has ever lived and ever will. He doesn't need your approval. If God condemns an entire nation to destruction, that's his right and none of your business. He's done it before and he will do it again. As the Creator of everything that is, God makes the rules. He defines right and wrong. If he decrees something, then it is morally right, by definition.