Random people being able to post content for thousands or even millions to immediately see, with no explicit gatekeepers prior to submission; this is largely a recent thing. And it makes sense that of course everywhere has rules, bare minimum basically nobody likes people spamming stuff, for example, even in cases where it's legal.
If you create a message board about model trains and some rando starts constantly spamming ads for their series of NFT's, I guess banning them is technically 'censorship', but you could also call it 'the bare basics of maintaining a functional community'.
I think that for platforms like Twitter and Facebook, perhaps it may make more sense to end up a situation more like newspapers, where you have more reputable papers like the NYT, WaPo, and WSJ that have stricter rules, and then you also have the National Enquirer or other random outlets that have little to no standards. If Twitter and Facebook want to have somewhat tighter rules where they censor people, that's fine, the people being censored should then just have options of other platforms with different or fewer rules. Just seems like the problem to me is that people expect these mega platforms to be all things to all people, when that's probably not realistic.