I disagree. If the deaths of millions of 'innocent' civilians is what it takes to finally free Japan and the Japanese people from fascism, then that is actually the greatest favor we can do for them. Only once Japanese fascism is completely defeated can Japan and China work as equals towards creating a better future.
Japan was not, is not, and will never be China's equal. Their culture and subsequent mentality render them unfit to co-lead Asia. They had a chance once; we all know how that went. See below:
From Chinese culture, Japanese adopted 忠 - loyalty - as their core value. Chinese on the other hand adopted 仁 - benevolence - as the core value. Chinese culture is all about overall feel and having a good end result while Japanese is about rigidly conforming to rules and expectations. Japanese loyalty is misplaced
The only way to deal with their national character is: 1. Dominate to complete submission, 2. Forcibly and comprehensively change their culture, in our case, Sinicise them, and 3. Once their core incompatible traits are suppressed, assimilate them into the wider Chinese identity, and the old 'Japanese' identity forever dies. If it can be done for steppe nomads, it can and should be done for island pirates.