However the true question here is more likely to be "what does unfair mean".
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.
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.
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.
Huawei/China Telecom/etc. notwithstanding, though they are not exactly social media competitors vs. Google/Meta.