I'm curious what they know about TikTok that isn't public. This seems too drastic for just trade posturing.
TikTok is basically a tool of [SOME NATION]'s military intelligence. Not going to say which nation, but this is well known in the security community
I'd like to see some evidence before describing that as anything more than a gut suspicion, though, and definitely not "public knowledge". This type of Executive reaction reads more like a response to a targeted threat and not just the general background noise of "all your base are belong to China" like over the past few years.