Third example is irrelevant because it's impossible to achieve the efficiency (reach) that social media has.
A book does not broadcast in the same way.
> Since when are social media apps considered broadcasters?
Not OP but they said should be, not is
Allowing a foreign adversary to consistently pump in propaganda just isn't something that should be protected by free speech... You, a citizen, are allowed to go find whatever media your heart desires. A foreign power is NOT allowed to force feed your propaganda. How is that not clear?
Free speech protects our ability to not be prosecuted for saying or viewing something controversial. Why on earth would that same protection be extended to a foreign power?!
You can't compare a popular bipartisan law to a hypothetical thing you just made up.
Peoples' votes matter
Moreover when there's 100s of issues at stake in any election you will inevitably have to vote for a candidate that disagrees with you on some of them.
Moreover the entire point of "rights" like free speech is that some things need to be protected beyond a simple majority.
We should also forbid Hollywood from selling movies in China, because as we've already seen that means the movies are being adjusted to get approval in China.
We should also forbid Chinese citizens talking to Americans, because they might convince Americans on a topic we don't can't allow American minds to be changed about.