By this logic, the US government should be able to ban any newspaper that is publishing articles that they don't like: it doesn't encroach on the freedom of speech of the reporters of that newspaper, they can just speak somewhere else. They don't have the right to say anything at that particular newspaper, just in general.
Of course, in reality, banning a publication (TikToK) because you think they may publish stories that you won't like (propaganda for Chinese interests) is an obvious violation of the first ammendment and a form of government censorship.
Freedom of speech is that an American person cannot be blocked by the government saying what they want.
There is nothing in the first amendment that protects you from where you can say what you want, nor is anyone entitled to give you a platform.
That's why the US has "freedom of speech zones" which are basically cages far away from where they should be protesting.
TikTok was banned because it's owned by a foreign government, not freedom of speech. If the Chinese government had removed their connection to it, it would not have been banned.
The reason TikTok being owned by China is considered a problem is because it could allow China to control what American citizens see on their timelines - the content.
> The reason TikTok being owned by China is considered a problem is because it could allow China to control what American citizens see on their timelines - the content.
It's the PRC control part that's the key here though. There's nothing banning even blatantly pro-PRC content on other platforms. You can find plenty of tankies praising China over the US to high heaven on places like Reddit.
Then it's just virtue signaling. If the message is not a problem, then who says that message is irrelevant.
Note: to be clear, I'm neither a tankie nor in any other way supportive of PRC policies. They're a horrible genocidal dictatorial regime with imperialist tendencies who are propping up other similarly horrible regimes like Russia or North Korea.
Just to give an example of what would be concerns of the platform aspect of TikTok, that would be concerns about the ability for the app to deploy malicious code to users' phones, or the amount of data that it siphons off legally. But those are de-emphasised in favor of their control on content, which is precisely what's supposed to be protected by the Constitution.