Is there a typo in the question? By definition censorship is already censorship. It's a tautology.
If you mean when does small scale individual censorship become systematic censorship and oppression?
in today's internet, with the public square is being privately owned, Twitter Instagram Facebook etc, small scale censorship by the private corporations, can effectively become systematic censorship, because they dominate the digital public square.
This is why myself, and many of my friends, are actively supporting the fediverse so that people's voices can be democratically supported, and not subject to corporate censorship.
This is at the root of the paradox of tolerance. If you tolerate intolerance, eventually intolerance dominates.
Robert Anton Wilson wrote about Big Truths and Little Truths. Similarly, we can talk about Little Censorship and Big Censorship. I don't know what those definitions are, but I'm sure that it's not just a matter of scale, because the Paradox of Tolerance applies at all scales. I think the difference lies between in what's being censored, things that promote intolerance. And then there are things outside of intolerance that most of us agree should be squashed -- child porn, hate speech, incenting to crimes against individuals, doxxing. But it's a fine line, and you could argue that it's better to not censor, and just make the the sharing a crime.
Personally, I don't have clear definitions around this stuff, but I do think the Paradox of Tolerance is a real thing that's been demonstrated countless times, and which should be heeded.
The tolerance intolerance discussion is interesting, and very sticky.
If speech is criminally intolerable, then it should be up to the criminal system to prevent that speech. Not digital platform providers to enforce their opinions. Or at least that's why I support the fediverse.
"If there be any among us who would wish to dissolve this Union or to change its republican form, let them stand undisturbed as monuments of the safety with which error of opinion may be tolerated where reason is left free to combat it. I know, indeed, that some honest men fear that a republican government can not be strong, that this Government is not strong enough; " - Jefferson, Thomas speech
Personally I fall on the the side of a free and open discord, we cannot be fearful of evil ideas, we must expose them to sunlight so that they may shrink away by the minds of conscionable people.
Rhetorically I've seen many internet arguments use the intolerance of tolerance idea, to shut down any idea they don't agree with. They wield it as a shield to prevent open debate. I think that hurts discourse, and finding common ground, it polarizes people in a discussion.
As well as small/large, I think there's a difference between legal/effective/practical censorship.
With legal censorship but not practical, I can tell my friends things, maybe pay anonymously, but at risk of legal prosecution and worrying about my ethics as a law-abiding citizen.
Media bias (for example) gives effective censorship for many, but if I care enough I can even start my own media and promote it as best as I can - and some people can be reached.
To some extent I think the three can balance each other out: for instance I wouldn't want anti-vaccination rhetoric to be the main thing people hear, but I do want freedom and opportunity for people to question scientific and medical consensus.
Personally I think social media is a fantastic tool and also a problem - but not a good place for a solution: so I tend not to worry about social media 'censorship'. Maybe I'm just out of touch!
To me it is blocking expression that presents no plausible harm to anyone. Yelling fire in a crowd to start a panic, making a specific threat, and intentionally spreading lies as to defame all strike me as harmful language and should be curtailed somehow. All expression of any kind not plausibly causing harm should be allowed and equal in the market of ideas despite my personal opinion of them which is a bitter pill to swallow when neonazis appear all to common. The is my opinion.
That really depends on who's at power currently. I'm pretty sure almost everyone agrees with you, it's just that people disagree on what's considered harmful to society.
There are people who think saying two men can kiss and love each other is harmful.
a governmental body. private entities, whether that be people or organizations, are not bound to the concepts of censorship like a governing body with real power over the people are.
I find all the rewriting of books and remaking of movies and tv shows I used to watched as a kind because they are inclusive enough to be strange. I knowing it is not a government effort. but why is the public trying to the kids now that if they do not have a culturally diverse friend group it is something wrong. we are trying to achieve equality not make race or gender something people do not think about. sorry i know this is a bit off topic but it is I want to talk about.
I'd say if you are unfairly depriving someone of an audience that would have wanted to listen to you.
Individually blocking someone you don't personally want to hear from obviously isn't censorship.
But if you have a monopoly on a platform and block everyone who would be interested in listening to someone, just because of your personal preferences, that is censorship.
But if virtually no one wants to listen to something and you block it, I would argue that's not censorship. E.g. no one should has to listen to spam or look at porn.
Of course those lines are blurry, but so is all of moral judgement.
It's more clear cut if you 'unrightfully' ban someone from YouTube, since it's a monopoly. Banning someone from lemmy.world who would have had an audience there is trickier, since ideally this would eventually lead to them and their audience moving to an instance where they are welcome.
That's why you would want your government to protect speech, since it is the biggest and most powerful monopoly. But in my opinion the same should extend to any large institution, like social media.
And I'm talking about censorship as a moral judgement free term, since I would argue there is some good censorship. E.g. banning CSM. I don't think it makes sense to call it anything other than it is.