Why do moderators behave as a separate, private sub-community? (i.e., why does the Teacher's Lounge exist in its current form?)

It's the same reason that your parents would shoo you out of the house or go to their bedroom when they needed to discuss something of gravitas, or the same reason that one-on-one meetings with your direct supervisor are done behind closed doors.

There's no reason to expect that any communications done by moderators should ever be public until it's ready to become public. It would give the moderation team a chance to refine certain messages or define policies amongst themselves before trying to communicate that out to their communities.

Additionally, the notion of it shields us from much of the drama that takes place in there. The only reason this one bubbled to the top was due to it being, quite literally, such a earth shattering event that we couldn't help but pay attention to it.

The stark reality is that moderators are and moderation is separate from the day-to-day notions of a community. They have to deal with a lot of sensitive, in-context stuff on a regular basis, and being able to lean on the experience or guidance (or sometimes another warm body to help in the trenches) of other fellow moderators is something key and valuable.

I think what's being lost here in all of this kerfuffle is that, while people want some kind of justice, it doesn't mean that all of a sudden we should just bust open the doors to allow everyone to pry into conversations that are generally private.

Rather than speak entirely abstractly, I thought it would be good to give examples of things I've done in the Teachers' Lounge which require such a private backchannel:

• I've pinged a mod on another site to share some (public) information on what I believed was a possible sockpuppet network on their site (and it turned out my guess was correct). Had this information been made public, the puppeteer would have known what signs of connected accounts we were picking up on.
• I've had a discussion with another mod about a delicate situation with a user in another chat room we were both in. This discussion - the details of which I cannot disclose - also ended up with me pinging a Community Manager. Again, it was important to maintain privacy for the sake of that user and the other folks in the room.
• I've vented about particular problems I've encountered in the course of moderating. I think a lot of us have, at one point or another. It can be good to let off steam in a controlled, private setting - again, where details about moderation actions remain unknown to the relevant users - while still being able to talk with mods across the network, who can likely empathize with the frustration. Plus, on ideal days, it has the potential to be a stress-free environment, because I don't have to pretend to be a perfect Stackizen. I'm human - and I feel like in the Teachers' Lounge, I can be more of an imperfect human and less of a perfect moderator.
• I've talked with mods from other sites about personally identifying information (PII), which can help us figure out if a user is creating new accounts to avoid a suspension or committing voting fraud. While IP addresses usually don't need to be shared between mod teams, simply saying to another mod team, "Yeah, we're seeing a lot of activity out of [insert city here]" can be quite helpful. Having this be public would clearly violate the user's rights of privacy. I would likely be instantly de-modded if I revealed information like that in public - and quite rightly so.

I'd also like to parrot remarks by terdon and Stephie, pointing out that the Teachers' Lounge is a place where mods can . . . well, paradoxically, not be mods for a little while. Everyone's equal, and nobody has to be a leader. That can be both relaxing and conducive to discussion and debate.

To be honest . . . I think mods really do need to be transparent, and I've striven for transparency in the almost four years I've been moderating Stack Exchange. But that transparency shows itself in other ways - commenting on answers I delete (even though usually only the answerer will see it), responding to mod messages asking for clarification (if the user is being constructive and wants to improve their behavior), hanging out in chat so I'm easy to reach if folks need clarification on a decision I made, commenting like crazy if I can, etc.

When it comes to accountability, I very much trust the Community Team to hold myself and other mods accountable for decisions we make. Obviously, relations between mods and the company at the moment are icy, to put it nicely, but these folks work hard and, honestly, do want what's best for the userbase. I can probably count on one hand the number of times I've seen a mod behave extremely poorly and the Team hasn't taken action in response - and maybe I don't need any fingers at all.

I know. It kinda sucks for everyone else to know that there are discussions happening behind closed doors. And, yeah, that maybe slightly fogs the glass through which users can glean what mods are doing. But it also protects the privacy of regular users, protects our privacy to consult with each other when needed, and keeps things running as smoothly as possible.

The Teachers Lounge (“TL”) is first and foremost a place where mods can ask for help doing a task they haven’t been trained for (unless you count the privileges that come with high rep status). There’s also a handful of tools that make mundane tasks easier. Being able to freely ask for advice and guidance is very important to get new mods comfortable in the role and provide experienced mods with feedback. Consider it peer coaching. Now, one could argue that this could happen within the site’s specific mod chat, but sometimes asking a wider circle is better.

Second, often enough a user is, hm, shall we say “difficult”? And may struggle with the concept not just on one, but on multiple sites. A coordinated effort can help to clarify what’s really going on (malice or simply not understood something?) and the mods do come up with better solutions how to either help a struggling user or block malicious activity.

In both examples it is very important that all participants can talk freely and in a protected (aka confidential) environment. Both for the moderators’ and the discussed users’ protection. Obscuring names wouldn’t help much - especially on sites with lower traffic, very few keywords are sufficient to get what post and therefore what poster is discussed.

Occasionally a CM may bring up something or chime it on an ongoing discussion about site policy. Not necessarily because it’s super-secret-let’s-exclude-common-users^irony! stuff, but because the moderators should be able to answer questions that may arise on various sites.

Of course, there’s not permanently something mod-related to discuss although there’s a “mod issues take precedence” rule. And if you have been working with others on a somewhat regular basis, you will chat about mundane things. Water cooler stuff. Moderators are just humans. Although expected to be good role models and to be leading their communities by example. It can be exhausting. Give them a bit of breathing room.