Dehumanizing others costs you part of your humanity. It puts you on the path toward becoming a monster. Yeah, it's only one step on that path, but the better answer is, don't start down that path.
Some people behave like monsters. You may have to kill them. But they're still people, and you still have to not dehumanize them, lest you dehumanize yourself.
https://en.wikipedia.org/wiki/American_mutilation_of_Japanes...
In particular:
>We learned about savagery from the Japanese ... But those sixteen-to-nineteen-year old kids we had on the Canal were fast learners ... At daybreak, a couple of our kids, bearded, dirty, skinny from hunger, slightly wounded by bayonets, clothes worn and torn, wack off three Jap heads and jam them on poles facing the "Jap side" of the river ... The colonel sees Jap heads on the poles and says, "Jesus men, what are you doing? You're acting like animals." A dirty, stinking young kid says, "That's right Colonel, we are animals. We live like animals, we eat and are treated like animals—what the fuck do you expect?"
Where is the human part of taking a knife to a man’s genitalia after you decide to invade his country?
If russians don’t want to die, they can just go home.