I'm less certain that it's a slippery slope than it is a fine line. The government does not appear to have a problem with the speech occurring on TikTok. It is not trying to apply censorship or forcing the app to close down. It tried to force it to be sold away from its Chinese ownership. It tried to mitigate the possibility that a foreign adversary can use the app as a tool for its own interests. Had TikTok divested itself instead of shutting itself down the dancing would have continued on.
the state as such consists of many entities, all these entities are not all pulling into the same direction.
divesting was never a real option, why would you spawn a US-based competitor - and it would cut you off from all the global content? just never a real good option