There are many chat rooms in the Ask Ubuntu space of the network. Of the three you mentioned, only Ask Ubuntu General Room is what I would call official, since it was created at the dawn of time when the site came into being for the purpose of being its chat room.
Back then the creator bot, or whoever was there in the primordial swamp, said
This is a general discussion room, but please feel free to create more subject-specific rooms (a single room with every possible discussion isn't very helpful)
And askubuntuers went forth and created many chat rooms for all the purposes for which they wanted chat rooms.
For example, they created the Downboat, whose meandering history I have elsewhere documented. Note that the room has been repurposed (or at least, its purpose has evolved).
They also created the Island of Castaway Thoughts. That happened because some users of the Downboat such as myself and Eliah Kagan would at times start talking about something in the Downboat relating to a post, and the discussion would become long and technical and contain large code blocks and so on, or the conversation in the room would gently veer into some other thing unrelated to moderation, so it was felt that in order for people to comfortably use the Downboat for moderation, there needed to be a room to bail out off-topic conversations into, and the Island serves that purpose.
There are many other rooms which people have created and used for their needs and interests.
I would like people to have
- autonomy
- empathy
and use those things to
- enjoy using chat
- achieve things they want to use chat to achieve
- allow others to enjoy and achieve things too by being adequately respectful, considerate and, when joining an existing room, on board with the spirit of that room
Especially to help the last point along, some degree of moderation is needed at times. And we have arrived at my point, which is that the purpose of room ownership is moderation. Poor room owners are expected, to some degree, to try to moderate the rooms they own. But room owner privileges are limited to being able to read deleted messages and to move messages from their owned room to any other room where they have write access.
Each room, depending on its purpose and its inhabitants, has its own moderation needs. The Downboat, for example, almost never has any issues that can't be completely dealt with by the ability to move messages (usually to the Island), so room owners of the Downboat are in a position to fulfill its moderation requirements. AUGR is a different story - in the past it was an unpleasant environment for me on quite a few occasions, and some of those situations were mitigated by interventions made by moderators.
Moderators have room owner abilities in all rooms*, and can also edit and delete messages by other users, so they have no need to be room owners. Someone once made all the current moderators of Ask Ubuntu owners of AUGR, but there is no particular reason for that to be the case. If any of the existing room owners were to express a wish to be removed as room owner (or if, like, their cat started using their account to move messages randomly as a prank), they could be removed. Since several moderators frequent AUGR, I do not think there is any need to add additional room owners (though anyone could post on meta requesting or suggesting the addition of room owners). Neither do I think there is any need for a policy to be formulated with regard to room ownership - room owners can be simply added (and removed) as per need, and the needs of rooms are many, various, and evolving.
* that is, all rooms on the chat server that Ask Ubuntu is on. There are many other sites on this server, but Meta Stack Exchange and Stack Overflow are on other servers, I think. Also, mods are shown flags for moderator attention in any room on the server, so a flag in any room will quickly attract a mod. Rude/abusive flags are also shown to all users who have 10k reputation across their sites, so those get handled even faster.