The First Amendment doesn't give any foreign entity any rights. There's no censorship of Americans here, whatever you posted on TikTok you're free to post on Instagram. In fact you can even still post it on TikTok, it just can't be in the Apple or Google app store and it can't be hosted on Oracle servers.

I think a closed door intelligence meeting is unlikely to just be them telling Congressmen scenarios they've already heard. I think they much more likely had some receipts. Some of the Senators in that meeting (from both parties) have sponsored a bill to declassify it and share it with the public, so we may find out.