Or TikTok would change their business to operate within the limits of the new regulation, which is something that cannot happen with an outright ban. A good compromise is to do like the EU with GDPR and not ban companies directly but still require them to comply with local privacy laws if they want to access the market. Foreign companies that don't want to do it can simply block European users (effectively self-censoring themselves).
A.K.A government surveillance and anti-privacy rules. For instance, I believe various data leaks have proved that Chinese police (down to the local level) get a literal feed of all public and private social media messages sent over Chinese apps. There's also a video floating around of some poor schmuck locked in a tiger chair by some Chinese police, being forced to apologize for talking smack about them in a private chat.
So you are saying they are not blocked by the GFW?