No it isn't. For instance, even though you seem to be mad about having your reach there limited by the choices of mastodon server admins, here you are freely expressing your opinions on a different website. You have not been censored.
Okay, Google removes your website from the search index. You have not been censored, after all, you are still on Bing. Oops, Bing also removed your Website. Don't worry, you are still on, err ... yandex.ru?
Yes, correct. Your website is not entitled to be included in any search index; many websites are not, for many different reasons.
This is a uniquely internet-era phenomenon, where people feel they are entitled not just to speak, but to be heard.
Nobody ever argued about whether the Wall Street Journal has an obligation to publish any article sent to them by anyone, or whether CBS is required to broadcast any television programming sent to them. It's an absurd idea.
