I think the primary argument for banning TikTok should be based on reciprocity rather than moral and/or security concerns. We can make similar arguments about the negative effects of Facebook, Instagram, and etc. even from the POVs of other countries, but the key issue here is that China heavily restricts foreign apps and services from operating in their market. If China is unwilling to allow US companies to compete fairly in their digital ecosystem, why the hell should we continue to grant Chinese firms unrestricted access to our market?