The heart of my question is in the title, but to provide a little info on what time periods I'm thinking of in particular here's some context;
I was listening to a podcast(Hardcore History) about the sacking of Carthage by Scipio Africanus of Rome. I was shocked to hear the details of how exactly it went down. I mean I've heard about cities being sacked but something about this one was particularly horrific. Polybius's descriptions of the dead and half dead being dragged into ditches. The chaos of buildings burning, people throwing themselves from roofs to keep from the brutality, etc. I'm sure there was also a great degree of sexual violence that went down as well. The most surprising thing to me was that it was said to have took 6 days to destroy. And still-- at the end 10,000 remaining citizens of Carthage were given some mercy and let out the gates. I can only imagine the horror of hiding for six days while everything you know and love is destroyed.
So what did people think of all this horror? Did common citizens and the soldiers who went to war have differing views? How about things like rape-- would a woman seeing her husband off to war tell him to remain chaste, or would she excuse these things as acts of war? And were people judged for their excesses during war-- for example if so and so had a penchant for rape or torture in war, would people look at them differently during peacetime?
BONUS QUESTION, if you have the time: I also know that at that time soldiers in the Roman army were landowners, who would have returned to their farms, family, and normal lives when the war was over.
One of the strangest things to me was hearing about these Romans back at home talking about honor and virtues such as that. They even seemed positively charitable and kind at times. It struck me as odd to think that these men weren't extremely calloused after committing holocausts of entire populations. I suppose I think of the example of the battle-hardened WWII vets who couldn't adjust back to normal civilian life after, who carried the harshness of war on their shoulders permanently. I would imagine killing men, women, and children for 6 days straight would have a similar effect on people. So what were these men like after coming back from war? Did they really just switch back to normal, sometimes kind men fit for civilian life? Or would they carry a harsh streak and a callousness towards civilian affairs?
So, I'll start by linking this thread, which includes both u/Iphikrates talking about the military side in the Greek context and me talking about the civilian side in the Hebrew context. Both of those responses are more about the psychological and less about the ethical side of your question.
On the ethical side, there is a decidedly mixed historical record. Frequently what you find in these discussions is a kind of melancholy. The rape and murder of civilians is treated as basically inevitable, but still tragic. Greek sources are very interested in this kind of pondering, paradigmatically in the story of the sack of Troy. Euripides' Trojan Women is a good source for a sympathetic take on the tragedy of the destruction of cities.
Here's Hecuba in that work (not my translation):
Ah, woe is me! This surely is the last, the utmost limit this, of all my sorrows; forth from my land I go; my city is ablaze with flame. Yet, thou aged foot, make one painful struggle to hasten, that I may say a farewell to this wretched town. O Troy, that erst hadst such a grand career amongst barbarian towns, soon wilt thou be reft of that splendid name. Lo! they are burning thee, and leading us e'en now from our land to slavery. Great gods! Yet why call on the gods? They did not hearken e'en aforetime to our call. Come, let us rush into the flames, for to die with my country in its blazing ruin were a noble death for me.
Hecuba is brave, and admirable in a way. But she's also been destroyed in every way that matters, dishonored in the way the ancients reckoned these things. Note the Roman attitude towards Hannibal or Vercingetorix et al.
I'll leave with a quote from the Iliad. Hector, prince of Troy, has just removed his helmet to reveal his face to his son. (When looking on his father's helmeted head, the child cried in terror.) Hector stands on the city gates and raises his son high while blessing him:
[My own somewhat on-the-fly translation]
Zeus and the other gods, may my child show himself, like me, greatest among the Trojans, great in power, and rule over Ilium. Some day, let someone say of him as he returns from way, "He is far better than his father" and may he bear the gore-dripping spoil of the enemies he has killed, and may his mother's heart be glad.
In other stories, the child is later thrown from that very wall for fear that he might indeed grow up to be a great warrior and avenge his father.
It’s actually a very contemporary question. Pillage and looting and rioting are happening right now. Those who were not involved and many who were , want to forget. People justify the horrors by saying their enemies deserved it somehow. There are lullabies talking about cruelties inflicted centuries ago, that are not mentioned in history texts. It was a part of life for the living.