Comment by lolinder
3. The government is concerned that having a company that's beholden to a foreign government control the algorithm that feeds the rising generation much of their worldview may not be a good long term plan.
This has a passing resemblance to (2), but the key difference is that the government doesn't believe they have control over the narrative on Facebook, they just know that a foreign government doesn't. It's strictly better from the perspective of the US government to have the rising generation's worldview shaped by raw capitalism (after all, that's how all of the older generations' world views were shaped) than to risk the possibility that an adversary is tipping the scales.
What I don't understand is why the politicians insist on talking about spying as the concern. The people who are pro-TikTok are pretty clearly skeptical either way, and "think of the children" is usually the most effective political tool they have.
Funny you mention Raw Capitalism:
It shows a point I like to bring up often that Capitalism and The Free Market are directly opposed. What capital (a fancy word for shareholders) want is an infinite money machine and that is easiest with a monopoly. Hence, banning a competitor that's doing too well in the free market.
To the other part, I consider your 3 and my 2 the same, the US doesn't want us getting Chinese info and has their own perfered sources instead.