See: War Crimes
Trying to sweep it under the rug is, IMO, morally wrong all by itself. If you're doing something, at least admit it. Not all of the things GP is talking about are considered warcrimes, and it's sometimes a word thrown around to make it look like we care about something after the fact, but we still do it.
But you need to consider this in the context of actual reality, where nearly all "war" is really a police action taken extrajudicially by ultrapowerful states against guerilla groups or civilian populations in order to ensure the dominance and power of wealthy global interests. Every war in the cold war was like this.
The doctrine of the acceptability of mass slaughter of innocents is how the people with weapons have chosen to use them in these non-existential "wars" but that isn't a justification for that choice.
If it's necessary to win a fight that matters, and it works, it is okay.
See: allied bombing campaigns in WW2 wherein we intentionally roasted thousands of babies and grandmas.
The self-indulgent alternative is a recipe for extinction. And you can't have much influence over the world if you're not there.
If you're not brutal enough, you just end up handing the future to someone more brutal, which is itself a wrong. Just like it'd be wrong to let the Nazis take Europe because you didn't want to roast babies and grandmas.