Pretty much every culture around the world in ancient times had some sort of moral explanation for why infanticide was allowed. Now that extra mouths to feed aren't an imminent threat of everybody dying, the practice is considered immoral
https://en.wikipedia.org/wiki/Infanticide
we aren't genetically different from those people, we just happen to live in a time where we don't have to make as many tough choices
I don't think anyone is claiming a genetic evolution. It has been a memetic evolution.
You see this with the Romans, too: they tell a city to surrender, it doesn't, the Romans conquer it and practice unspeakable brutality on whomever's left.
So what's happening? They have very limited resources, you forced us to expend them, maybe lose some of our own soldiers, and waste a valuable campaigning season - ok, now you pay the price, and let this be a warning to the next city: if we tell you to surrender, you'd better surrender.
What if the city does surrender? Are those people killed or sold into slavery anyway? I don't think historians bother recording those episodes.
Typically, no. The attacker may leave the city entirely intact, or may place their own proxy government. They may take the elites of the city as prisoners, either as punishment or as insurance.
Its very questionable if he was all that nice to the Medians and Assyrian cities.
'Good guys are the ones who worship the right god(s) and therefore we get to kill the bad people next door', or 'Good guys are guys who serve the King/Emperor and anything that advances his glory is good', 'Good guys are cultured people and everyone else is a barbarian' etc.
You’d previously get word of mouth of what was happening (with lots of us vs them, dehumanizing, etc.). Now you’d get to see it ‘in person’ in 4K @ 60fps on YouTube.
It’s easier to say (and think) ‘yeah, those bastards deserved it’ when you aren’t seeing a very human person have it done to them up close.
Which is a good thing.
I think it comes down to economics.
Ancient cities were primarily administrative and trading centers for the surrounding territory. Most of the wealth was coming from outside of the cities, it was just collected in the cities. You could kill off most of the people in the city and still keep most of the value because you still have the infrastructure that lets you control the surrounding territory.
By the time you get to the modern era, cities are producing a lot of value of their own. If you kill off the people, you've gotten rid of the whole reason why you want to capture the city.
>https://en.wikipedia.org/wiki/Infanticide
At least half of the history in the wiki describes major civilizations and religions which absolutely banned the practice. Ancient Egypt, all Abrahamic religions, ancient China... Apparently many people did thought infanticide was immoral and did ban it.