Now I'm wondering. Let's assume a Hubzilla forum channel that's configured like this:

• Default profile is kept away from directories and follow lists
• Custom channel role for fine-grained permission control
• Opt-out of search indexing is activated
• Can see my channel stream and my posts set to Accepted connections
• Can send me the posts from their channel set to Accepted connections
• Can see my default profile set to Accepted connections
• Can see my connections set to Accepted connections
• Can see my file and image folders set to Accepted connections
• Can upload/modify my file and image folders
• Can see the web pages of my channel set to Accepted connections
• Can see my wiki pages set to Accepted connections
• Can create/edit web pages in my channel set to Only those who you explicitly allow (so the admin doesn't necessarily have to do it all themselves)
• Can edit my wiki pages set to Only those who you explicitly allow (so the admin doesn't necessarily have to do it all themselves)
• Can publish posts on my channel page (‘wall’) set to Accepted connections
• Can send me direct messages set to Everyone on Hubzilla
• Can like/dislike profiles and profile stuff set to Only me
• Can chat with me doesn't matter because the Chat app isn't installed
• Can quote/mirror my public posts in other channels set to Only me
• Can administer my channel set to Only those who you explicitly allow (to be able to have more than one admin)
• "Member" contact role adds nothing to what's inherited from the channel role
• "Moderator" contact role adds Can administer my channel
• "Editor" contact role is the "Member" contact role plus Can create/edit web pages in my channel and Can edit my wiki pages
• "Moderator/Editor" contact role is the "Moderator" contact role plus Can create/edit web pages in my channel and Can edit my wiki pages
• ActivityPub and Diaspora apps are left uninstalled, no other connectivity than via Zot6 available
• Superblock is installed for much more effective moderation
• Privacy groups (essentially Mastodon lists on Tony Montana amounts of coke) are installed so that the admin can directly address to a subgroup of forum users instead of only always all of them
• There's one privacy group on the forum channel that contains all forum members; the forum channel admin(s) post(s) to that privacy group by default and never in public
• Additional encryption is activated for those who want to send really private DMs, and who don't even trust the hub admin who has direct access to the SQL database

Consequence:

• With no additional protocols activated, only Hubzilla and (streams) users can join the forum; users on Mastodon, Lemmy, PieFed, Pleroma etc. can't find it or interact with it in any way
• ActivityPub-based Fediverse server apps with their total lack of understanding of Hubzilla's permission can't meddle with them
• The forum channel is neither listed in any directory nor on anyone's list of connections, and search engines like Google don't crawl and index it either; the only way to know about it is from advertising or hearsay
• Those who do find the forum channel can't see or do jack on it unless they're members; all they can do is send DMs to the forum channel unless they've been Superblocked
• The forum channel may have its own webpage(s) and/or its own wiki(s), but only an inner circle of a select few forum members is allowed to edit them
• Nobody can use the forum channel as a channel source, i.e. automatically repost any content from the forum channel (yes, this is a thing on Hubzilla and its descendants)
• Direct messages are actually private messages; they're made private not only by whom they're sent to, but also by who is permitted to see them; with ActivityPub disabled, they can only go to servers that know, understand and heed this permission; in addition, there's encryption available
• Even messages from the channel admin(s) are restricted and not public; only forum members get to see them and are permitted to see them; they don't show up on the pubstream of someone's private single-user hub; they can't be shared/quoted; they can't be repeated/boosted

Would you still insist that with all these efforts taken, this forum channel is no more private than a Lemmy community?

Also, with ActivityPub off, would you consider this forum channel as being in the Fediverse, what with the typical Fediverse definition being "it can connect to Mastodon"?