The History of China and Japan's Barbarism

i recently learned about the japanese invasion of china and saw the real fotages of nanjing genoside, which were unbelievably horrifying. My questions are, have those tragedies influenced the chinese in making them as aggressive as they are to day? And why have the japanes still not apologized for it? Why is japanese barbarism not talked about, though it is an important part of second world war history? I think if you look at the magnitude of the death tolle i think the hollow coast is worse.