> even in many democratic countries, in terms of political correctness, you don't want to talk about some subjects in public.
Yes, and to the degree that happens, things disappear from the public sphere.
I'm German, and the Nazis are not a happy subject one wants to talk about, but being forbidden from talking about that would be so much worse. And while not everybody "wants to hear about it", there is no difference between "in public" or "in private" really, it what matters more who you talk to, or who overhears it. Neo-Nazis don't want to hear about the Holocaust, Antifa has no problem with it, for example.
The way Tiananmen is taboo in public discussion in China is an entirely different thing I would say, simply because it mainly comes from the CCP and repression, rather than the opinions of people. People may say they "don't feel the need" to talk about it, but if someone talked about it in public and wouldn't stop, they would be stopped, and people know that.
> Does it really mean not being able to say it at all?
Yes, for all practical purposes in context of what we're talking about. Maybe this will help explain:
https://plato.stanford.edu/entries/arendt/#CitPubSph
> For Arendt the public sphere comprises two distinct but interrelated dimensions. The first is the space of appearance, a space of political freedom and equality which comes into being whenever citizens act in concert through the medium of speech and persuasion. The second is the common world, a shared and public world of human artifacts, institutions and settings which separates us from nature and which provides a relatively permanent and durable context for our activities. Both dimensions are essential to the practice of citizenship, the former providing the spaces where it can flourish, the latter providing the stable background from which public spaces of action and deliberation can arise. For Arendt the reactivation of citizenship in the modern world depends upon both the recovery of a common, shared world and the creation of numerous spaces of appearance in which individuals can disclose their identities and establish relations of reciprocity and solidarity.
In China one might even say the CCP allows criticism, but tries to keep that public sphere non-existent, regardless of whether it is supportive or critical: https://gking.harvard.edu/publications/how-Censorship-China-...
But I agree that this also is a problem in the West, the public sphere isn't exactly healthy, though at least it still exists. A quote by Arendt I posted recently also applies here, both to China and the West: https://news.ycombinator.com/item?id=21175000
And from "Origins of Totalitarianism":
> The deprivation of humans of their rights, the killing of the juridical person in them is just a precondition of their being totally controlled, for which even voluntary agreement is a hindrance.
What is voluntary can change, and this is not permitted with some things (or under totalitarianism, a lot of things, until history gets rewritten and then it's not permitted to not change them).
People in the West do that all the time, too: pretend like "that's just how the world is" and they are adapting to it, rather than, as they say that, acting in a way which, together with millions who act similarly, creates and continues the situation they claim to simply adapt to. We don't fear the secret police, we just don't want to be frowned on, we just don't want to lose sleep or our appetite. That's much worse, but two wrongs still don't make a right.
I don't think the CCP is "the villain" and the rest of the world free and saintly, at all, it's just that I can't make an exception just for the CCP and pretend 2+2 is 5 in their case. So while I mean all my "cynical" (I would call it blunt) words, don't take them as just aimed at the CCP (and people who may think they might not be sooo bad etc.)