It's absolutely absurd to think that the Chinese government doesn't use TikTok to influence non-Chinese users. They'd be incredibly foolish not to do so. And the difference here (as compared to other nations, including the US) is that that Chinese government gets to legally, deeply meddle in the affairs of Chinese companies as a matter of course. Running influence campaigns on a platform owned by a company out of the Chinese government's reach is a bit more work; they get to do it essentially "for free" on TikTok, plus, as a bonus, they'd have access to data they wouldn't get from a foreign-owned platform.
I think any country should have the right to protect its citizens from influence campaigns led by other countries. Whether or not that protection can and will be effective, and whether or not it's a smokescreen for other purposes (e.g. protecting Meta's market share), is another matter, of course. And certainly some kinds of protection -- such as a US TikTok ban -- will be wildly unpopular with a lot of people who love using it.
Aside, Congress is not a courtroom. The legality of the law is on trial, not its motivation or the basis in fact of its public justification.
However, returning to your witty witch-hunt comment, I don't think it's 1:1.
Consider that by that line of reasoning it's very difficult to prove that intelligence agencies ever do anything at all. All they have to do is say "no we didn't, and we don't have to allow anyone to have a close look".
In fact, if we simply relied on governments and faceless corporations to always tell us the truth, we'd probably manage to be even worse off than now! Haha.
There exists a difference between investigating or rejecting that with uncertain sources (esp. large and secretive institutions) and specifically accusing. Or between a witch hunt and demanding that (for example) food manufacturers should have to disclose their secret ingredients and some processes to the government to make it harder to put poison or addictive drugs in there without telling anyone.
No. This is about using reason to anticipate and prevent problems, not dumbly waiting around until the actualized problem stares you in the face and it's too late to do anything about it.
But if you want evidence, all that is needed is the evidence that China and the US are adversaries.
Then your standards of evidence are too high, and least for making decisions in this area. It's like you're working in computer security, but you demand evidence a vulnerable system was actually hacked and used maliciously before you're willing to take action to patch it and clear out the infiltration. It's foolish. Patch the damn system.
A theory that can explain everything explains nothing.