It makes perfect sense with the way business works in 2019. Regulatory capture means big players in a given country want lawmakers to attack foreign (and local) competition, and the lawmakers are happy to do it because it pays off. The fact that Chinese competition is Politically Threatening just makes it easier to convince lawmakers to act.
Foreign countries will exercise their control over local companies and subsidiaries (for population control, for tax revenues, and for corrupt personal gains to politicians) just like we do, and will tap into any data they can for political advantage.
All the big countries want control over data, which means they want services to be operated by local subsidiaries or want the foreign companies to be subject to local laws. Their uses for the data may vary and the other demands they make may vary but in the end all of these big capitalist societies (even the ones pretending to be communist or whatever) function the same way: The people with money control the system in order to make more money.
Even before TikTok was being attacked as an arm of a foreign surveillance state, Huawei was being targeted the same way (rightly or not - probably correct). This framing is a success with the general public as well, and is currently being deployed against international gaming companies like Blizzard, Epic and Riot based on their Chinese (Tencent) ownership stakes, even if they're based in the US.