It sets an absolutely obscene precedent that a government can globally restrict information

Again, the information is still everywhere.

Even global terrible actors like Russia and China haven't succeeded at that.

Actually, the Chinese Wikipedia used to have a systemic bias in favor of the CPC before China blocked it, after which the bias was changed.

because the entirety of Wikipedia is open source and would be mirrored in the country instantly

It's a bit elitist to restrict information—weapons of revolution—to those who know how to find a mirror website. Why don't you survey the Chinese nationals in-person to see if they know how to get on Wikipedia? Plus, to avoid block evasion, no mirrors would be able to edit Wikipedia.