No one says that all sites should honor China's laws for visitors from China. No one claims that all sites should honor Saudi Arabia's laws for visitors from Saudi Arabia.
But magically the GDPR must be followed by the entire world if a visitor shows up from France.
China has the great firewall, the EU tried something similar under the "think of the children" excuse, which promptly failed.
Also a lot of people speaking out against China had to find out the hard way what some western companies will do when you speak out against a cash cow that will happily kick them out if its rules are enforced.
USA set the precedent when the FBI arrested Dmitry Sklyarov (a Russian Citizen) for working for a Russian company that apparently, while in Russia, broke US law.
It would be like Wendys slagging off the Thai king on a billboard in Dakota, then an employee of Wendys went on holiday to Bangkok and was arrested.
That's actually a counter example to what you're trying to say.
In this case you are arguing that Russian law should follow a citizen, where as the US said it shouldn't. So the "precedent" that was set (if in fact there was one set) in a case from 20 years ago in which the case against the accused was dropped, was actually that your laws don't follow you around.
The precedent set was that the EU could arrest a citizen of the US for working for a company based in the US if that citizen happened to go to the EU on holiday.
The Meng Wanzhou case had the EU being able to extradite a US citizen from the UK for breaking EU law.
No one says that all sites should honor China's laws for visitors from China. No one claims that all sites should honor Saudi Arabia's laws for visitors from Saudi Arabia.
But magically the GDPR must be followed by the entire world if a visitor shows up from France.