On the other hand, it would be quite surprising if tiktok wasn't collecting everything it could about its users.

This is literally not new information. Social media tries to harvest as much data as it can. Data analysts frequently quit and instantly start using ad blockers and other protective measures for a reason.

We definitely shouldn't normalise this sort of surveillance, whether it's simply for advertising or for more nefarious purposes. China already banned apps like Instagram, Facebook, Snapchat and Twitter, so was that due to anglophobia or is it ok when China does it, but not when the US does it?

I agree with you on some level - it's definitely not cool to only focus on TikTok, because these surveillance machines are IMO all equally problematic. But most Lemmy users have a dim view of all mainstream social media apps because they all suck with regards to user privacy. But is TikTok hated on more than Threads or Facebook? I really don't think so. And the narrative that any criticism of the Chinese state must be sinophobic is total bullshit. The Chinese state is just as sleazy and authoritarian as any other large nation state. They all deserve criticism when they use these digital panopticons for political purposes.