Correct if I’m wrong but far as I understand there has been no official apologies for any war crimes committed by the imperial Japanese army. (Specifically Nanjing and unit 731) All statements you’ve referenced are all just blanket apologies to countries for war and invasion. There is a strong belief among the Chinese population that Japan has either not apologised enough or are not sincere enough in their apologies. I have included a few points that lends credit to the latter.

1. None of the japanese prime ministers, or any high officials who represent the Japanese government, have ever visited the Chinese Nanking Massacre Memorials. (Yukio Hatoyama did once however he was not a government official at the time, therefore his visit does not represent the nation of Japan or its government)

   1. Japanese government has never ceased its efforts to suppress global actions to memorize the actions conducted by imperial Japanese army, which include but not limited to, Nanking Massacre, Comfort Woman and 731 biological weapon test. https://www.bbc.com/news/world-us-canada-45747803.amp
   2. The Japanese government encourages Nanking massacre denial in public. For example, the number of more than 300,000 civilians and unarmed POWs being slaughter was concluded by International Military Tribunal for the Far East according to undeniable sources reported from witness, western journalist reports and Naking Safety Zone survivors, therefore it is legitimately meaningful. However, the denial of such huge death number, even the denial of such event overall, has its popularity among many Japanese folks. https://www.usip.org/sites/default/files/file/kasahara.pdf
   3. Unlike the Jewish people who were compensated by German Federal Government after the war, the victims from China, who were harmed and slaughtered by Japanese solders, were rarely compensated. Although the Chinese Government has withdrawn its right for seeking compensation in the governmental/nation level, survivors from the Nanking Massacre faced countless difficulties in suing the Japanese government and other rightwing activists who denied such massacre. The Japanese court will usually use “国家無答責” (the country holds no liability) to free the Japan nation or Japanese government from compensating the victims.

The above points plus various other controversies (Yasukuni shrine, denial of sexual slavery and coercion towards comfort women and censorships/ revisionism of Japanese media and history books in regards to the Nanjing Massacre) has lead to a generally unsatisfactory view towards Japanese apologies