I don't use TikTok, but I assume there's also a concern over foreign influence of a nation's voters? Whether you use TikTok or not, that'd be a potential concern. Entire countries could be subtly influenced by supposed algorithms. A finger on the scales or whatever they call it.

I've long wondered if we might (past or future) see a social media company be successful mostly because, in their infancy, they were indirectly funded by intelligence services in exchange for data access. However, I assume as operations scale, it gets harder for that sort of link to stay secret.