It sounds unfair from the perspective of companies wanting a right to market access, but companies do not have rights, people do. People's right to freely choose where they get their information from trumps companies' non-existent right to have the government shut out their competitors.
Reciprocity is there - follow PRC media filtering (read censorship) laws. There's a reason google and facebook both had internal projects to engineer PRC compliance to reenter PRC before internal corporate dissesnt shut it down. The only reason western platforms were booted from PRC in first place was not censoring calls for violence / terroism post 2009 minority riots because muh freedom of speech, but actually because following PRC filtering requirements = onerous moderation (read expensive) that every PRC platform had to follow (and pay for). Few years later western platforms get roasted for radicalization/violence and realized PRC was precient in social media censorship and forced to adopt their own bulk moderation systems and realize some tweaks can get them back in PRC market. Like if US wants genuine reciprocity, just do a JV like in PRC that favours US interests. Even PRC hasn't implemented something as bold as a force sale or "ban" for largely following domestic PRC laws.
The punchline is that it amounts to a bill of attainder, so in order to avoid that criticism, they're going to create censorship laws for all media and simply promise to selectively enforce them.
TikTok isn't even novel either. Before TikTok there were Vine and Musicly. Removing TikTok isn't speech suppression since other platforms can easily take their place.