What are the criteria to label things as "disseminating propaganda"?
Also, you'd follow the laws. Doing such thing as you suggested violates a lot of US laws.
And in fact, China does have laws to force operators to follow other Chinese laws, including censorship laws. Technically, Google and FB and all those banned firms are leaving China voluntarily because they decide not profitable to follow those laws.
So if certain laws are passed to shut out Chinese propaganda outlets, that'll be totally fine.
But again, this will be banning individual outlets, not just platforms. China probably will retaliate to bann individuals as well.