China can't directly influence US policy, and they mostly don't have any interest in doing so outside how it influences our trade relations. Sure, it's bad if they're doing that. But Musk, Zuckerberg, and the rest of the ultra-wealthy are directly creating US policy, both by serving in unelected advisory positions and by outright buying US politicians. Just like China, they are not working for America's interests, they are working for their own interests. They are removing hard-won safeguards for their employees, their customers, and Americans in general; and they are removing accountability for themselves so they can exercise that power over the people who live in the US with impunity.
US billionaires are far more dangerous to US residents than China is, and this law gives them even more influence than they already had by removing the only significant competitor that was not owned by a US billionaire. If this law had impacted all social media equally, I would be a huge advocate. But as it is, it's just another handout to the US's richest and most influential people. It's a bad law, and will make life worse for the people who live in the US.
China is far, far more powerful than Zuck or Musk.