Well, it's about some sort of control. Narrative? I don't know. Something to do with China and power struggles. But I still find tiktok to be beyond irritating. Just another black hole for internet addicts to tumble down. Mostly stupidity.
The stupid parts are mostly what are shown because as usual the people showing them equate popularity with worth. If someone gets a million views for doing a silly dance while someone else only gets a thousand for talking about an important geopolitical issue which do you think is going to be portrayed as "representative" of the app?
The vapid famous-for-being-famous content is what will grab the focus because it's more efficient clickbait.
But if that's all that existed on TikTok they wouldn't care about it.
There are also people posting stories and footage directly from places like Gaza and then even more people are sharing that content and talking about it. The USA/NATO lies are being widely exposed and that's a big problem for the establishment because they can't threaten and bully TikTok over content the way they do platforms like Facebook and Xwitter.
Agencies like the FBI actually have people embedded inside domestic platforms (see: Twitter Files) as well as "cooperation" agreements with other government departments which allow the government to dictate which accounts can remain active and which topics can and can not be discussed without resulting in punitive action against users.
The Biden administration is currently fighting a court battle over this very issue of interference with first amendment rights on social media platforms and they tried to set up an entire "ministry of truth" (Disinformation Governance Board) to further that goal but had to shelve those plans when people learned about it.
In this age when everyone has a cell phone and is potentially a citizen journalist as well as having access to unfiltered information from across the world all the democrats and republicans have left is narrative control which is why they're resorting to increasingly draconian measures, like banning TikTok, to retain it.