There's more than enough reports from outside the US that credibly allege TikTok is a critical factor in the radicalization and recruitment of the far-right and militant Islamism [1][2][3].
Conspiracies about Zuckerberg wanting to dunk on a competitor aside (that may or may not be real, and I'm heavily inclined to believe they are true), the threat from TikTok is real, this application needs to be exterminated at all cost before China completely tears apart our society.
[1] https://www.bpb.de/lernen/digitale-bildung/werkstatt/560523/...
[2] https://www.zdf.de/nachrichten/politik/deutschland/radikalis...
[3] https://www.tagesschau.de/inland/regional/hessen/hr-wandern-...
You can find literature to support that claim for Youtube, Facebook, and Twitter, not just Tiktok. The Making of a Youtube Radical was a big story back in 2019. Facebook won the election for Trump in 2016. Twitter is owned by a Nazi who routinely boost far-right conspiracy theories.
The answer isn't banning Tiktok but passing strong privacy and data legislation that affects all social media platforms. Not just Tiktok. US social media companies have been pulling on the seams of society far before Tiktok arrived.
I could swear the US passed a law targeted at TikTok last year. The law was precisely targeted to prevent any collateral damage on any of the American social media companies that are guilty of most or all the bad behavior leveled against TikTok.
We don't, and we won't (and these platforms are just as easily manipulated as TikTok), but we can, and that's what matters.