Better question would be "when the last time you googled something without prefixing it with 'reddit' to get good results" 🤭

online communities seemed to be going to discord

That can also be seen as "nature healing itself" in context of giant AI botnets scraping the whole internet every second. It's only natural to go private nowadays.

I think your point of view would be more relatable before AI happened. I don't see how it addresses AI problem anyhow. "Societal progress" isn't something that has self-worth. I see that as a tool of improving QoL, but if it's not only stopped improving QoL but actually started making it worse, than it's not something to pursue, and actually something to actively sabotage.

I agree that Discord shouldn't be trusted and might turn out to be a bad actor some day. Anyway, the more general tendency of moving away from public spaces is a right and natural thing. So it's best to do the same as with Discord but without Discord. In the upcoming era of AI hiding knowledge is a good thing to do, and I'm personally not used to this yet.

While I agree with many of these takes, I believe there is more to this. For example, your point about defense from falling into panopticon by speaking publicly about things doesn't actually require publicly speaking about anything other than politics. I mean, you can still hide all professional, creative or fun talk and still have the benefits you listed covered by only ever publicly talking about political issues. Another issue, is that publicity and interconnectedness of all discourses we have nowadays, increases a homogenuity of thinking patterns, in other words it hurts the diversity of the ways of thinking, that is also something that can be improved by more people going private and having closed interest groups in chats invisible to public web.

Where is your evidence of this?

Everywhere? Every decade humankind becomes more uniform worldwide, but especially last few decades.

It is a mistake to think pushing everybody to talk only in private will increase the diversity and quality of discourse. It will NOT, it will collapse conversations into simpler more reductive narratives.

I feel like over the last two decades everyone on the internet was pushed to talk only in public, even more so, on the few biggest platforms only.