If China is going prevent US companies from doing profitable business within its economic borders I don’t see why the US should allow Chinese companies to engage in profitable businesses ventures within its country.
They get to do whatever they want because they're a dicatorship. Saying the US government should be allowed to do something "because China does it" is a real slippery slope. 2. We aren't talking about oil extraction or car sales here, we're talking about something which is explicitly a speech platform. They are different.
It's not just a "company" being banned, it's the government telling you that you can't use that companies services for your speech. Imaging the US government banning the The Guardian because it's not owned by US citizens. That's the same thing as banning TikTok because it's not owned by US Citizens. The government has no right to ban newspapers or websites which are otherwise engaging in legally-protected speech. You have a right to hear what they have to say.