It is really easy to fix, make it mandatory to provide a scan of passport, driving license, or other official ID when registering for a social media site. Or it they are children and don't have such ID, a parent has to provide theirs. Of course the issue is it needs to be a global effort otherwise people will just put a VPN on and sign up in a country that doesn't have such requirements. Plus people will complain it is an erosion of their civil liberties.
That said, other countries police it much better than most Western countries. Posting anything even vaguely controversial on social media in China, assuming you can bypass the restrictions, isn't likely to be beneficial to your freedom or even potentially health. Even leaving a dodgy hotel review can land you in prison in the middle east.