What do you think about human rights in war in Confucianism cultural traditions?

A few days ago, I read The complete annals of Đại Việt and learned that the Ming people had many good laws while ruling the land of Giao Chỉ. But my friend sees it differently: he said that the Ming people had many evil laws, so Lê Lợi attacked them and brought independence back to the people of Giao Chỉ.

I also see your idea differently. I told him that Lý Thường Kiệt attacked the city of Yongzhou in the Song dynasty and killed many of the people who lived there. My friend said that Lý Thường Kiệt killed because the people of Yongzhou did not want to surrender. And he meant, I think, that Qinzhou and Lianzhou were not like Yongzhou because they both surrendered, right?

I question my friend’s idea, because in The Complete Annals of Đại Việt I found that many Việt kings (or emperors) often had harsh laws against people who failed in war, similar to how the Ming people viewed the Việt. And after Lý Thường Kiệt ruled Qinzhou and Lianzhou, wasn’t he robbing people’s assets and setting fire to the city?

So, were the Ming people not wrong?