Let me tell you that for any international public figure who has business and public connection with China, three Chinese political figures are untouchable.
1st, Mao Zedong. We Europeans are all told by many political narratives particularly left from cold war time, Mao is a "dictator that murdered millions of people" . Such narrative only looked Mao's mistakes in his decision-making in his later period (he exercised those bad decision however often due to his illusion that CPC members as whole do not treat people well anymore thus he mistakenly call people to rebel, which ended into total anarchy and loss in every dimension). However, heavily neglecting his enormous positive contributions to mankind especially to the Chinese. He is the real key person that prevent Chinese nation from falling into abyss with outstand private virtue. To most Chinese, respecting chairman Mao is not a choice but a faith passed through generations.
2nd, Xi. The taboo of offending Xi is much from the political institutional reasons. The operating of Chinese society, unlike the west, requires the leadership dignity to maintain respected, as important signals for the functionality of the whole party and its ruling in China. Belittling and mocking Chinese leaders, signaling a challenge against this governing legitimacy thus receives painful penalty. Definitely many west-valued people dont understand it and even dispose it. But if anyone wants to have positive connections with China this is something worth very serious learning.
3rd. Sun-yet Sen. Sun is another China-savor character whom even Mao Zedong needs to pay respects to. He stood up in China's most dangerous time to launch revolution, building the republic and offering the modern civilization to the Chinese. He was well-known as the founding father of modern China and dedicated his whole life into liberation of Chinese people. For Chinese, he is another faith symbol that shall not be insulted