Earlier quoted context omitted.
TikTok should be banned in the US. China banned all of our homegrown social networks, its pretty standard international precedent to ban theirs, given the security risks.
China didn't specifically "ban" US social networks because they were US social networks. The companies themselves didn't want to comply with Chinese laws so they cannot operate there. It's the same as Facebook now threatening to leave the EU if they have to comply with EU data protection laws.
2) On "China didn't ban ...", that's the case for Google and Linkedin China, but it's actually a kind of "soft" ban that the cost to meet the regulatory requirements is too high to afford even for biggest companies in the world.
3) FB case was a bit different. It was never given any opportunity to operate in China, so FB didn't "chose" to leave. We would never know what FB would do if given the chance. Maybe leave all user data there inside the great wall, as Apple does in its special version of iCloud in China.