A) they’re a Chinese owned company
B) China asymmetrically has never allowed US social media (amongst practically all major internet properties)
C) We cap ownership of foreign owners of US media. TikTok IS TV for the young generation.
But apparently he thinks it helped him win (would love to know if that was actually true, which is probably impossible to calculate), so who cares about all these other principles!
* Thinks he can help negotiate some sort of deal that keeps TikTok here fairly, or
* Sees an opportunity to do a grift/accept some bribes from ByteDance/get some control over an effective propaganda engine.
This would be a minor "infraction" compared to what he has already done. I don't see this moving the needle one bit.