Geographically distributed servers are the norm for large services like this. Way more efficient to serve from something near the consumer than from across the globe. That's why Netflix ships Open Connect Appliances to local ISPs so that the most common content can be served directly from the ISP instead of having to bounce from some big Netflix server farm.
The issue has never been where the US servers are hosted, the issue is what level of access the CHICOMs have to it. And what they can do with the app tracking too.
This is 'merica, we want our spying to be done by big businesses and giant, faceless government agencies.
"Alexa, how much access does the CCP have to my info from TikTok?"