The government of China doesn't have a First Amendment right to free speech in the United States.
If Facebook/Twitter/Alphabet were to be acquired by Chinese interests that would almost certainly be blocked by CFIUS just like the potential Broadcom/Qualcomm acquisition was a couple years ago.
I personally believe that freedom will prevail and this kind of race to the bottom towards censorship and executive branch unilateralism is sad.
Whatever level allows them to dictate behavior.
> If funds controlled by Chinese nationals bought stakes in Facebook/Twitter/Alphabet, wouldn't that put them in the same category?
Of course.
> What portion of ByteDance would have to be owned by non-Chinese people before it would be in the clear?
Of far more significant is whether ByteDance's leadership are subject to Chinese jurisdiction.