Foreign governments don’t have a first-amendment right to manipulate American public opinion, but Americans have a first-amendment right to consume foreign propaganda. The fact that TikTok is operated by a Chinese company isn’t a secret, and neither is the fact that the Chinese government has a great deal of influence over Chinese companies and can use that influence to further goals that it perceives as contrary to US interests. Americans who choose to use TikTok anyway have the right to make that choice, because “I don’t care that my social media is being manipulated by a hostile foreign power” is an ideology which, while perhaps foolish, is still in the same category as any other political ideology.