I mean, it's not just because it's outside the US. It's because ByteDance is legally required to collect and hand over data to the Chinese government. And it's well beyond what any other social media app does plus unnecessary for the functionality of the app. This is not about xenophobia. This is legit about trying to stop the Chinese government from spying on US citizens who are too ignorant to realize what that app is. They just care about stupid videos.

Edit: for example, if you're on a government network, there's a good chance half your calls to GitHub hosted content will timeout with no response. Why? Because GitHub has load balances that direct traffic occasionally through a server hosted under Chinese jurisdiction. That route is explicitly blocked so any time your request gets sent there, it simply fails. China is not a trusted foreign government under US law. And the Chinese government found a novel way to legally spy on the United States and the citizenry are too stupid to prevent it so the government is trying to fix it without calling the public a bunch of idiots like they are.