Sure you can. By the ethics/morality of 1945 what the Nazis were doing was considered evil just as it is today.
No, the Japanese government/military back in WWII was evil all by itself. In some ways they were worse than the Nazis. Bit of a judgement call I admit but the Japanese were not “bad” merely by association with Nazis…they were evil all on their own.
AFAIK Japan was the only country in WWII to engage in biowarfare killing up to a million Chinese (and supposedly some of that lingers yet today in animal populations). Look up Shiro Ishii and/or Unit 731 and read up and that nice little buried note to Japanese contribution in WWII. All sorts of nastiness to make your soul cringe including things such as giving prisoners gangrene and watching it progress and vivsection of live people.
How about enslavement of 200,000 “comfort” women to sexually appease Japanese soldiers? This wasn’t the random rape that sadly seems to be part and parcel to wars. This was systematic, organized enslavement.
The atrocities committed in China/East Asia are pretty well documented with the Rape of Nanking just being emblematic of it all rather than the exception.
Look up the Bataan Death March in which 20,000 prisoners died on a forced, 55 mile march. That again is emblematic of POW conditions that were nightmarish.
“Just a bunch of stupid ocuntries blowing the f*ck out of each other”? I wish I lived in your world where the moral clarity is so simple. The world I live in things get a lot more gray. War is a horrible thing to get to and perhaps you can say it is stupid to get there in the first place. But how you prevent the Nazis and Japanese from embarking on their plans ahead of time without going to fight them is beyond me. They tried that with Hitler and he kept on keeping on till the Allies went to war. The US was restricting oil shipments to Japan as a way of trying to peacefully get them out of east Asia. The Japanese responded by attacking Pearl Harbor to get us to stop. Tell us what the smart move would have been so all the horror of WWII culminating in droppping the atomic bomb could have been avoided?