Let me correct you, it's the Chinese people who shed blood and tear against the Japanese, whether they are lead by the Nationalists or the CCP. If there is a victory, it belongs to the people of China, and the party that can represent the interest of the people.
When the corrupted Nationalists got ousted, it was the will of the Chinese people, because they no longer represent the interest of the Chinese people minus a few oligarchs, CCP was CHOSEN by the Chinese people instead.
Sure CCP is no where near perfect, but so far I'd say they did a pretty good job turning China into the largest economy in the world within a few decades WITHOUT WAR, lifting billions of its people out of poverty, providing cheaper products to third world countries making the world a better place to live in, and making barbaric nations founded on piracy and slavery panic and deranged.
What you are essentially doing is downplaying the will of the Chinese people, pretending whatever is left of the Nationalist today somehow still represents the entirety of Chinese people, which is absurd. The Nationalist in Taiwan today is nothing but a proxy puppet of the US, they didn't fight the war against the Japanese, their ancestors did, along with the Chinese people.
The CCP did little to defeat Japan. It was the Nationalists who did the fighting and the dying. As for Japan being shackled by what happened 80 years ago, that makes no sense. Better to look at the 80 years since the war - and compare Japan's behavior with China's. Japan has been humane. China and CCP - murderous. CCP killed 50 million of its own people, and trying to institute its own Greater East Asia Co-Prosperity Sphere.