I will never understand why private companies curating their platforms is equated with censorship. In China (and elsewhere) a central government curates acceptable speech. If you don't comply you go to jail. In the "West" you might get kicked off a platform, which diminishes your reach, but doesn't extinguish your speech. You can always find another soapbox. Or start your own, as one recent ex-president demonstrated.
I suspect it may be because your definition of "free speech" is too narrow. You operate from the perspective that free speech only exists in the form that is protected by the US constitution, and therefore anything not covered by that text cannot possibly be an instance of censorship.
The error is assuming that everybody else agrees with your definition.
This is a good point - Youtube/Facebook/Twitter/etc. don't currently have the ability to arrest, try, and imprison you. The bill of rights applies to the US government to prevent it from abusing that power.
Though a de facto oligopoly in the social media space means that your reach could be greatly reduced (though not, as you note, eliminated) if you are deplatformed. I imagine that some politicians, entertainers, and businesses could see large effects.
Being delisted from Google search could also be an issue for businesses due to Google's search dominance.
The difference is there can be 100s of twitters, and they require voluntary usage. There's only one government, and you are required to abide by their rules, so restrictions need to be placed on the government.
If twitter and the government work together (e.g. twitter banning people that disagree with the government to get favors or avoid punishments) then that should be treated in a similar lense as government action.
The problem, though, is that there is one ginormous twitter, and the other twitters are pretty much like fleas on an elephantine body. Or it can be Facebook. They deplatform you, and you and your business may as well not exist at all.
It becomes interesting if it turns out that there indeed exists a symbiosis between the US government and social media companies wherein the latter are compelled to do censorship laundering on behalf of the former, maybe in exchange of their balls being not so tight in the regulatory vise. After all, it’s not censorship if a private company does it, right? Right? (wink, wink)
IMO, the problem isn't that private companies exercise censorship (and it is censorship even if it is a private company), it is the amount of power and influence that individual companies wield.
You might consider the fact that these "private companies" products and funding are significantly influenced by government policy. Besides, you totally miss the point of free speech if you think controlling the audience of said speech is irrelevant.
