You find prescriptions for animal sacrifice, violence and other such gruesome behaviours. It is entirely incompatible with Buddhism.
At this point, I still don't know. I don't know Chinese and history of the text. But there seems to be a lot of contradictions that I am afraid to jump to conclusion until I am further updated.
It would be problematic to say that Confucianism has always been the mainstream ideology of China. Depending on the time period at times it was Mahāyāna Buddhism that held greater sway. After the Song Dynasty onward especially Confucianism picked up momentum again, though before that for a thousand years a lot of people in China, I imagine, had little to do with Confucian texts as they were either illiterate or just had less interest than in Buddhist works. In the Tang Dynasty the state was often more interested in Daoism than Confucianism and Buddhism. Before that for several centuries Buddhism was very mainstream at all levels of society.
This does not disprove what I said about humanism of Confucianism and Taoism was the foundation for the successful growth of Mahayana Buddhist in China. Can you offer another explanation why Mahayana has become successful in China and Vietnam but not in other countries?