The first amendment doesn't apply here. You can say whatever you want anywhere else on the internet. You can print what you want anywhere you want. You can distribute what you want anywhere you want. Bytedance refused to sell TikTok so it's being shut down. They could divest, but they didn't.
It just isn’t the Wild Draw 4 some people imagine it to be. You can’t commit fraud or libel or false advertising and claim First Amendment protection. Similarly, there are levels of scrutiny when the government claims national security to shut down a media platform.
The opinion actually assumes without deciding that First Amendment scrutiny applies, so I don't think it "absolutely" does. (But yes, it probably does and Sotomayor and Gorsuch would decide as much)
