It’s not worse for you personally. The US government can request and use warrants for information collected by all of those entities.

The US cannot request information on Chinese citizens in China because US companies are restricted from operating in China. They don’t have any significant data.

On the other hand China now has a very valuable and large presence in tiktok here in the US and can access any collected information it wants on Chinese citizens in the US and any other user. I imagine it doesn’t take a warrant either but I’m unfamiliar with their protocols.

So it’s likely not worse for you personally, especially if you’re a typical American who is unsupportive of their government and its foreign policy.

For the average citizen, probably not, but imagine you are a celebrity, politician, government contractor, tech CEO/employee with access to IP. It's not that difficult to hash out someone's algorithm to get enough of a psychological profile on the person to initiate a detailed social engineering campaign.

Because TikTok can be used as a weapon by China. Democracies have a weakness - enemies can influence the population and therefore the government. Russia does this quite effectively in my opinion (one example is Slovakia).

Because only spying from American companies is allowed. /s

In all seriousness though, it isn't. People are generally simply trying to fit in, so hating on anything China is viewed as good and everyone sticks to it.

We know because of Snowden how the US government has access to all (most likely way more) of the same data they are now worried China has access to.