I wouldn't call it a gotcha to celebrate bannings on one day, and bemoan them the next, depending on the website. That was AndytheBear, that wasn't me.
I respect the right of free association and if a club doesn't want some people, it has the right to get rid of them.
The picture changes when you are part of the general public's communication infrastructure. You are no longer a "club", you are the public square. The "Digital Commons."
I get your argument, but the devil is in the details. How do you define when a website has become large enough to be considered part of the Digital Commons?
1M registered users? 10M posts??
This is also a reverse incentive for web companies to be successful- knowing that reaching that point you define means accepting government oversight of content moderation policies.
As you said- this approach is something we see in Communist China.