As a queer person who uses TikTok, I think you should take some time to challenge your assumptions and get some more information. This video might be informative:
https://www.youtube.com/watch?v=3MYEtQ5Zdn8I should correct a mistake I made earlier: all of my numbers cited are likes not views. The TikTok promoting vaccines was seen 3.5 Million times. There are many queer creators with videos in the millions of views, and many more with videos in the hundreds of thousands.
Still, I don't think its reasonable to expect niche content from obese people to perform as well as generic content from normative people. I also don't think its reasonable to expect trans content to perform as well, given that a substantial portion of the US population still doesn't want to recognize or legalize their existence.
Yet, there is an abundance of queer content (content that sought me out, I never told TikTok that I'm gay), much of it quite niche. TikTok sends me enough gay male twink armpit fetish content that I don't realistically think you can say they're making a serious effort to suppress it.
If you're focusing on hashtags and not algorithm suggestions, I think you don't have a strong grasp of how TikTok works. All of the cited sources are quite old, so perhaps it was too early for folks to actually have time to use and understand the service.
Your claim that there is nothing threatening to China or TikTok economically is suspect, given the algorithm has also suggested Uighur muslim genocide content: https://vm.tiktok.com/ZMR1RhcUj/ - there are many more. This one has 65k likes. I also had no trouble searching for Taiwan and finding content that is quite hostile to China. I've had the fyp send me content directly critical of TikTok itself.
> “In practice, most of these hashtags are categorised in TikTok’s code in the same way that terrorist groups, illicit substances, and swear words are treated on the platform.”
The implementation details of an app aren't necessarily meaningful in the way you suggest. Twitter does something similar; I can type #isis #gay #weed #sex, and now Twitter has code that handles lgbtq, terrorist, and illicit substance content the same way.