Ed Morrissey

This is not a First Amendment issue. To the extent it's a constitutional issue at all, it could be an Article I Section 9 issue. TikTok could argue that a bill targeting them explicitly and solely is a form of a bill of attainder. That might be an interesting argument too, but I suspect that federal courts will see this as a commerce issue, and that Congress has the authority to act in the realm of international trade as well as national security, especially in concert with the executive. 

No one is losing an opportunity to speak. Americans have other platforms for speech that are just as easy to access. There is no constitutional guarantee that foreign governments or their proxies can operate propaganda platforms in the US, especially when it also operates as a suspicious data-trawling service for a hostile government.