Because non-Chinese companies cannot compete in the Chinese market place without strict handicaps. Some cannot participate at all.

However the true question here is more likely to be "what does unfair mean".

There are tradeoffs to protectionism that are inherent disadvantages in the strategy itself that doesn’t need someone to make it a disadvantage. Otherwise all countries would be protectionist all the time.

Tik tok dominating is just good old outcompeting the competition.

Protectionist strategies create less domestic competition, resulting in underdeveloped industries that would die off in the face of real competition. So if Chinese companies are insulated from outside competition then in theory they should have a harder time developing globally competitive products. If we continue to allow TikTok and other Chinese products it is not without inherent benefits of increased competition driving better domestic competitiveness.

Of course it just all looks like we are getting screwed because TikTok is outcompeting despite all this, but banning or hobbling it will just make Facebook et al complacent and likely even less competitive in the global market.

We need the competition, basically, if for no other reason than the fact that a competitive market is what underpins healthy capitalism.

Plus, subsidies are simply another form of protectionism and the US heavily engages in this too. We can’t pick and choose when protectionist policies are applied because everyone is doing it in certain industries.

I make widgets, you also make widgets. I can sell my widgets in your location, minimal to no restrictions.

You can't sell your widgets in my location. Would you as a seller of widgets think that is fair?

I know the reality is more nuanced than that but people are talking about reciprocal agreements to at least ensure some sense of fairness.

Taking a random stab: one argument could be that competition drives down profit margins. By reducing competition, China makes their tech artificially profitable locally, allowing them to compete in international markets on an uneven playing field.

It’s basically a subsidy to their tech and AI industry. Same effect as US corn subsidies making American junk food exports endemic.

US companies like Meta, Google, are banned in China. Chinese companies are not banned in the US. US investors are barred from making controlling acquisitions of Chinese companies. Chinese investors are free to gain ownership in any US company they like.

The rest of the world is generally playing on a level globalist playing field of free trade and open competition. The theory for decades has been that if the world treats China like every other country and then over time they will become more open. But this theory has been disastrously wrong. China’s communist party is a mercantilist country where the government and private industry act together as one.

> Chinese companies are not banned in the US

Huawei/China Telecom/etc. notwithstanding, though they are not exactly social media competitors vs. Google/Meta.

Chinese companies are not categorically banned. Huawei had to do more than be Chinese.

I think you can still buy an iPhone in China, but the only Apple services that appear to be available are the App Store (some apps such as VPN apps and news apps are obviously unavailable) and Apple Music.

Usually services in China are run by a local partner.