Give me a break... what, you'd rather just let said totalitarian government pump their propaganda into the US? This is a great example of following your moral principles right off the cliff.
What makes you think the propaganda won't be pumped in if the US app is sold to a different company?
If it's sold to a US company then it will be our intelligence agencies pumping the propaganda, not theirs. Which is an outcome I'm more amenable to, considering that our intelligence agencies generally have more of an interest in the stability of American society than the intelligence agencies of China.
See also - Facebook is American owned, yet that never stopped assertions that it was used by foreign adversaries to pump their propaganda.
So if it's propaganda either way, then no loss will happen?