Imagine for a split second that the strongest government in the world is constantly attempting to cause the overthrow of your legitimately popular government, despite it being popular and significantly beloved by almost all people there. This external, most powerful government in the world tried to cause unrest in every possible way, including funding all opposition groups and organizations regardless of their violent/genocidal intent (e.g. Falun Gong, Islamic terror groups) and cause unrest on your borders (Pakistan, Afghanistan, Korea).
What do you do? When good faith polling shows that you're popular and fulfilling the needs and desires of your country's working class but a foreign press tries to speak about the terribleness and need for overthrow, do you just let that happen with more money and propoganda than you can possibly provide to support yourself? Or do you censor the BS and report to your population that these images/ideas/orgs are actually subversive and attempting to change the government they legitimately love.
In this hypothetical situation, what do you propose? Allowing the propaganda but claiming it's wrong has failed in many projects, and resulted in massacres once fascism won (Chile, Indonesia). Just trying to set up a wall of no information works for a bit, but info can cross anyways (USSR). Allowing limited access if you search for it but not allowing it's widespread propagation is the method of china. A VPN allows you to see it all, but it can't be spread too widely before it is stopped from being viral.
Do you have a better solution? Because this is how China presents itself and how the Chinese population sees it