There's literally tens of thousands of human nosed there. Innocent men, women, and children among them.
Even when koreans were willing to work for the glory of the empire, thousands of working class koreans were massacred by Japanese vigilantes(regular people) and some government forces.
Koreans were willing to help the pan-asian cause, but the Japanese leadership and many ordinary Japanese exploited that trust. The whole issue with confort women is that those women thought they would be working in factories for the war effort like many other Japanese women but were instead sent away to military brothels.
No matter how hard the Koreans tried to integrate into Japanese society, Koreans were not equal. Korean yangban culture is trash but Japanese samurai culture led to millions of deaths in East Asia. Literal Japanese Nazis like Ikki Kita were more progressive than normal Japanese cornservatives, actually advocating for political and social equality for different ethnicities and races in Japan.