Imagine you tune into something and it's just Bin Laden or related stuff. If you don't find it interesting it's not like you're going to just sit there for hours watching it. Most likely you'd just find a different site if they kept shoving it down your throat. And, in fact, even if you somehow had to sit there for hours watching it, it's not like it's ever going to convince you to decide to convert to his sect of Islam and go become a Jihadist. The point I make with this is that people can only really be significantly influenced on things they don't already have preformed opinions on. And even then it tends to be quite brief, because more natural opinions start to coalesce pretty quickly. See - basically every war the US has ever been involved when the other country is some place most people couldn't even find on a map, at first.

IMO the real threat the US perceives isn't TikTok manipulating information, but them not manipulating it. Look up information about the Gaza War on YouTube and you'll be inundated with various sources promoting a uniformly pro-Israel narrative. The relatively low views on these hits (no recommendation had more than 400k views) for such a hot topic, with premium placement in the search results, suggests it's not resonating or organic, to say the least. But that's because, again, I don't think the goal is to actually get people to watch this and suddenly start cheering on Israel or whatever. Rather, I think the idea is to encourage people to think that they hold a minority view, and motivate them to self censor their own views and opinions. And that's pretty hard to do when you have this massive 'uncontrolled' site openly allowing people to express their wrongthink, and it not being artificially downranked.