You two are hilarious. WHAT COUNTRIES?
Vietnam? That was a French COLONY.
Korea? That was a Japanese PROTECTORATE since 1895, which she annexed in 1910, right around the same time as the US was annexing the Phillipines.
Indonesis? That was a Dutch COLONY.
Maylasia, Burma? They were a British COLONIES.
Manchuria? That was a Japanese SPHERE OF INFLUENCE since 1905, just like the British dominated the hinterland of Hong Kong, modern Guangzhong.
Much of WWII was Japan fighting various European powers and America over who would control the colonies of Asia, not Japan invading sovereign Asian countries. In fact, the only sovereign country in Asia with any internal consistency - Thailand - was a Japanese ally in the war, not a target of Japanese invasions.
I suggest you try that argument on the Koreans. You might not get the answer you’re expecting. As for the rest, the Dutch, French, and the rest were not murdering the natives wholesale, and the Japanese were. Shall we examine the only real American colony of the time, the Philippines? You do realize why the Filipinos ended up fighting on the side of their (cough!) oppressors, don’t you? Ask a few of them who were there.