Chinese are able to express negative opinions without any retribution (beyond their posts being deleted/moderated). What China doesn't accept is challenges to its power structures. Meaning protests, boycotts, unions, organising, public lobbying. Every large business or voluntary organisation has Party members appointed to ensure they don't interfere with the Party's power or strategy.* Sharing a VPN or negative opinion to one friend is fine, sharing to everybody you know on a stage is not.

* https://madeinchinajournal.com/2021/07/15/will-there-be-a-ci...