Comment by zuminator

The first amendment applies to US law and the rights of US residents, not to foreign multinationals. The USA can and does restrict the speech of non-Americans in America, such as with respect to political campaign funding.

Plus, criminal speech can be restricted in any case. If it's determined that the TikTok app is violating the law or facilitating the commission of criminal activity, the distribution of that app could itself be deemed a crime, or even worse for app stores, subject them to civil liability.