Quick outline of why TikTok is so uniquely dangerous:
- The Chinese government treats communication networks as their personal hoovering-attachment for any data they might want. Companies are required by law to operate as an arm of Chinese intelligence, both in terms of giving information and in terms of manipulating what information people on their network are allowed to see.
- It's not just your TikTok data. It's photos and files on your phone, your contacts, your messages, basically anything that the app with its too-permissive permissions can get its hands on, can potentially go up to Chinese intelligence.
- TikTok is not structured like any other app. It has features like custom-downloading and running arbitrary binaries from its central server that honestly don't even make much sense except as spying apparatus (consistent with #1).
- What China might do with this unprecedented level of access to everyone's phones is malevolent in a different way than, say, Facebook's access to everyone's data. Like Facebook they have the ability to e.g. influence an election, but they also have the ability to try to blackmail an individual to compromise them, or do for-real torture in the real world (say by tracking down a dissident via TikTok spying and then having one of their little Chinese-police-in-America units grab them).
Basically I don't think any government should have that kind of access to access people's private communications or design the algorithms that dictate people's social media experience, but definitely not China's in particular.