I don't know where to start.
Some quick points to consider.. about East Asia unity, do you know wht there is a north and south korea today? The US naively drew a line through half the peninsula in Aug/Sept 1945 and gave the northern half to the Soviets. So they got filled with communists, setting the stage for the Korean War. Far more Koreans would die in that war then the whole 35 years when it was part of Japan.
So you spent some time in Korea. Ok great, I have visited it too and enjoyed my time going through the Seoul shopping streets late at night, walking around in Gyeongbokgung castle, or seeing the tanks or Korean wooden warship at the Korean war memorial. But.. remember that South Korea has been a dictatorship until 1988. That means much of the population was under state control education. It is not a scholastically honest place. Some reading homework...
https://fsi.stanford.edu/publications/divided_memories_history_textbooks_and_the_wars_in_asia
https://www.nippon.com/en/in-depth/...s-history-textbooks-and-the-wars-in-asia.html
https://parkyuha.org/archives/4368
As for unit 731... I'm sure none of the documentaries that you have watched mentioned anything in the following.
https://en.wikipedia.org/wiki/Unethical_human_experimentation_in_the_United_States
I don't think you understand the holocaust and genocide in general... Japan carried out none of it. There were massacres and fair to call them war crimes. But the atom bombs were war crimes to be the same definition. But no genocide.
Have you consider the atrocities that the Nationalists Chinese have carried out on other Chinese? Consier the following quote:
The military was formed through bloody and inhumane conscription campaigns. These are described by Rudolph Rummel as:
This was a deadly affair in which men were kidnapped for the army, rounded up indiscriminately by press-gangs or army units among those on the roads or in the towns and villages, or otherwise gathered together. Many men, some the very young and old, were killed resisting or trying to escape. Once collected, they would be roped or chained together and marched, with little food or water, long distances to camp. They often died or were killed along the way, sometimes less than 50 percent reaching camp alive. Then recruit camp was no better, with hospitals resembling Nazi concentration camps like Buchenwald.[45]
https://en.wikipedia.org/wiki/National_Revolutionary_Army
Or how about CKS's the river flooding, killing 500,000 or whatever ridiculous number of Chinese
https://en.wikipedia.org/wiki/1938_Yellow_River_flood
Bear in mind the Japanese weren't committed so many of the killing in Japanese controlled areas. Japanese controlled areas had Chinese manned armies even, with guns. If the Japanese were really that bad, then why didn't these Chinese not rebel? Maybe the Japanese were tough on control but more or less reasonable? Imagine that?
https://en.wikipedia.org/wiki/Collaborationist_Chinese_Army
https://en.wikipedia.org/wiki/Wang_Jingwei_regime
And finally, one more point, after Japan was defeated in WW2, had the Japanese Army been allowed to remain in China under the command of CKS, then that Imperial Japanese Army could have been utilized against the Chinese communists. Afterall, in all honesty, CKS hated communism more than even Imperial Japan. And the Imperial Japanese hated communism more than CKS. Even though that huge Imperial Japanese Army in mainland China had to disband because of conditional surrender, some few Japanese still voluntarily fought for the Nationalists Chinese after WW2.
https://defence.pk/pdf/threads/what-is-your-impression-of-china.638471/page-3#post-11818850
Enjoy your homework.