The saying "There are no winners in war" is a pure moron play. It's the trite stuff amateur script writers put into TV shows.
It's fine to declare that nobody should start a war, as an OPINION.
It's fine to state that lots of people are "losers" in war, as a fact.
It is, however, objectively false to state that there are no winners in a war - the winners are the winner, and most people are mighty happy about that. When the NAZIs decided to roll tanks and making the Polish people into losers, and then they decided the show the French how to lose a whole other type of Tour De France, Panzer style, making more losers, it became mighty important for some body with a better moral compass to come along and be winners. Had the allies not WON that war and not been WINNERS, Europe would be a mighty dark place (well, in all but skin colors of course). Had the allies not been WINNERS, it's possible that even the US and Canada might have fallen, depending on the progress of Germany's physicists and whether the Americans had been stupid enough to buy into the "everybody loses in war" crap and thus NOT do the Manhattan Project, and NOT do the Liberty ships and the massive production of planes and tanks and jeeps and trucks, etc.
For those who'd like to dismiss the whole violent misbehavior of the Germans of that era, perhaps you ought to read some damned history of the Pacific basin to see just how necessary it was for the allies to WIN there too. Try reading up on the "Rape of Nanking" and those spiffy little misdeeds of the Imperial Japanese Empire which were actual war crimes. If you're too wimpy to face it all, just start with Unit 731 and look into other happy little "incidents" like the happy little meals on Chichijima island
Younger generations are far too ignorant of history to make any profound statements about it; their teachers were too-often the old former sixties hippies, or even worse: air-headed youngsters TAUGHT by them - people who started shoveling wads of cotton candy into the brains of the little urchins in their care before they themselves had any life experiences in the real world. Those warped idiots playing teacher were far too busy stuffing their students' brains full of crap about prophylactics and alternate uses for dental dams, lots of newly-discovered genders, boys and girls being interchangeable, Marxism as a reasonable thing that might finally work if the right people got to try it, everybody deserving a trophy, etc and not nearly enough about how to read, write, and do math at grade level, how to read a map, where Western Civilization came from and how and why it arose, and how to reason like a person with an actual brain. People with functioning brains can actually face the fact that the world is a harsh, unforgiving place with a LOT of really psychopathic people in it, some of whom lead nations and start wars. It does not generally matter why they start them, when the psychopaths start wars, somebody else damned well needs to come along and WIN them, or the human race descends into a nightmare run by those victorious psychopaths and the masses of amoral drones who willingly serve them as they grind the innocent into the ground.
I knew too many people who served in that war to just stand by and watch some idiot who knows nothing of value try to re-write history or pretend that what was done by the allies was not ABSOLUTELY NECESSARY and justified. The wonderful Japan the world knows today, that is, as much as any other nation, a "good actor" on the world stage is only possible because, in LOSING that war (and losing it the WAY they lost it), they learned that their emperor was not, in fact, a God.