But it's also worth addressing.
As near as I can tell, it is unfounded; there is almost no evidence to support it. The one potentially shady thing I know of that TikTok got caught doing was checking the clipboard every second, which it no longer does. TikTok's explanation is that it was an anti-spam feature. I know of no network analysis showing they were sending back the clipboard contents, or that they are sending anything other than normal analytics.
(Also, as an aside & for what it's worth, I personally think the data collection of Facebook is far worse than anything alleged against TikTok. They require you to provide your real name, they encourage you to give tons of other personal info, & they use trackers to tie your fb profile to your browsing history on non facebook websites. Then they sell targeted access to this profile to any advertiser that cares to pay, as their primary business model.)
(As a second aside, if TikTok is somehow gaining access to more personal info than standard analytics stuff, I would view that, for iOS devices at least, as a security flaw. I'm not that familiar with Android, but I assume the same applies there.)
Lastly, if TikTok is doing something nefarious, the proper way to handle it in a country ruled by laws is to have laws against the nefarious activity and prosecute the company for violation of said laws.
The president waking up one day and declaring TikTok bad and banning it is ridiculous, authoritarian behavior.
IMO :-)
This is the same reason why Europe should be also wary from both CCP and US administration.
Trump's narcissism notwithstanding, the natsec issue with these apps isn't that US citizens are communicating with others, including foreigners. It is that they are installing what may very well be Chinese government spyware on their phones, with detailed tracking and keylogging.
FWIW it would be interesting to keep an eye on what kind of permissions and access some of these PC gaming platforms have to peoples' workstations, as well.