1. the regulation and AI for Douyin and TikTok is completely separate and different. On TikTok I frequently see anti-China videos.
2. From my experience on Chinese social media, the debate on policies and voices on public grievances are common place. When there is a huge public blacklash for something the government is done, it might be filtered to tone down the "heat", but I believe that is to reduce the chance of the incident develop into uncontrolled populism and social unrest. For these incidents, the government usually acts really fast to address the incident. An investigation could be launched, and any government official found with wrongdoing is promptly sacked.
I find for public grievances, the government is already addressing many of them. For others, the government usually acknowledge it after sometime and add it to its working plan. For example, a lot of people were criticizing air quality in early 2010s. By 2013, government's added air quality to its working agenda and released a series of comprehensive plans to address air quality. For the past 8 years, the work on air quality has been consistent. And you can see how much air quality has improved in China. Same thing with poverty, education issues, left behind child, health care etc. So I believe the government does listen to the public, even though public backlash might be filtered at the moment.
A group of people demand change, but changes need time, government and society need time to adjust. The group that demand change could think that its their right to demand change and world should listen. They might use tactics such as massive protests to demand the world's attention. But mass protests in China massively dense cities could cause financial and live lost to others. At that point the group that demand change inadvertently infringing on others right to peace and good health. This is fear. The fear is not about criticisms for the government, but its about hot blooded public demands that grow into populism and hate. And populism creates irrationality in the society that doesn't help to address the issue and might cause more damages. Criticisms are to be addressed in the framework set out by the political system and in an environment that allows rational debate and negotiations.
Filtering on Chinese internet is about controlling populism, any kind of populism. In fact, articles that stoke mindless love for the ccp, personal admiration for xijingping, or hot blooded nationalism are also filtered. Also the platforms will try to remove fake news, spam accounts soliciting money, child pornography, and other illegal content. This stuff seems to be practiced in western internet.
I don't know this is the right way to do things though.