Earlier quoted context omitted.
I actually think it's naive. Sure if military personnel or state department use TikTok that can create security risks, but the same is true with any other social media network. The additional data that TikTok tries to gather from the mobile OSs is insignificant compared to what you can get from videos that people take willingly. Russian soldiers use VK, that doesn't stop OSINT researchers tracking them down on there.
Military personnel is not what this is about, it's about the data of all the citizens in the US. It's about manipulating public opinion, sowing divide or a thousand other options.
Granted collecting say interest data based on viewing figures would be a precursor (I suppose it's likely that TikTok could figure out if a customer leaned left or right politically). But again that's not what the complaint is about.
It's also hard to ignore that TikTok's responses are at face value reasonable (such as evaluating touch patterns to identify bots... that's obviously something they have to do given the predominance of bots on social media platforms).