IMO, it matters why they're banning it. The reasons are a worry about "national security" as related to Chinese propaganda and manipulating opinions. Those two things are speech, which makes it a valid avenue of challenge.
Why something is done matters to US law just as what was done matters.
And personally, since the spread of propaganda and manipulation is happening on Facebook, only targeting just the new kid on the block is terribly suspect. Especially when there's no plans to address the existing platforms and their use by foreign entities.