Meta-conversation shouldn't be taboo

I think in some significant subset of such situations, almost everyone present is aware of the problem, so you don't always have to describe the problem yourself or explicitly propose solutions (which can seem weird from a power dynamics perspective). Sometimes just drawing the group's attention to the meta level at all, initiating a meta-discussion, is sufficient to allow the group to fix the problem.

I think the problem is that you're clinging to being 100% truthful and precise which is making you think you need to instantiate a meta-conversation when you really don't. In scenario 5, you can just start talking to the person next to you about a different topic, "Oh hey did you see X, what's up with that?" If they start chatting with you then you can pretty clearly tell they don't want to listen to the chatty girl either. The fact that you two are having a conversation also signals to the chatty girl and other people around that you both are less interested in what she has to say. You guys can then keep talking near them, move away, etc. Other friends may follow you or join your conversation and it doesn't matter if that girl was the chattiest of chatty people. She'll be left talking to her boyfriend + 1 and if the +1 is not interested then he'll come up with some excuse to go to the bathroom or something.

This happens subconsciously most of the time, but sometimes you have to take the initiative if you want to resolve the situation. This is way better than coming out and giving a meta explanation to everybody about how the conversation is boring or how you're bored or something. Firstly, you're not risking that you may have misread the room. Maybe your friends actually thought the girlfriend was interesting and if you speak up and say you're bored or that she's talking too much you'll get shot down and probably annoy them. Secondly, this is a lot cleaner for the girl as well. She doesn't suffer any overt embarrassment that she would otherwise experience had someone told her straight to her face in front of multiple people that she talks too much.

Fully putting your feelings into accurate, precise words and expressing them to a group is not always the best solution to uncomfortable social situations. I bet it's not the best solution the majority of the time. But that doesn't mean you just have to suppress your emotions, you can express them in more subtle ways that maybe aren't 100% explicitly honest.

I agree that there are awkward and non-awkward meta conversations. However, perhaps on average, meta-conversations can tend to be awkward because they:

1. Implicitly criticize a person or group's interaction style, which may come off as a personal insult (i.e. the way you behave naturally leads to problems, thus it is incorrect/less than ideal)
2. Illuminate an unspoken social hierarchy or stable conflict, which persists stably due to not being outright stated or described clearly (i.e. a person accepts being interrupted because he tacitly considers himself lower on the social hierarchy, but can deal with that fact and glide with it smoothly as long as it is unsaid)
3. Make one too aware of their interaction style. Even if it is not a criticism, it can lead to a "glitch in the Matrix" moment for a person, even momentarily, they think about that thing they may be doing even accidentally, and their thinking/fluidity of interaction slows as a result.

I think in a larger sense, there is an implicit hierarchy in many social groups that rewards status based on the ability to mesh automatically, and just get a lot of unspoken norms. It becomes almost a game of chicken or intimidation: whoever can deal longer assenting to status differentials or awkward moments while keeping quiet "wins" this game, and thus is more worthy of belonging. To some, it seems, the need to clarify or criticize any element of the unspoken social rules may signal a person's inability to "vibe" with however the social order has ended up, signaling that they don't belong among the people who "get it"

I think that, despite mentioning Larry David, you didn't consider the most useful technique when it comes to steer a conversation, which is to be an asshole while using a hefty dose of humor. 

In my experience, if you try to have a meta-conversation, no matter how delicately you put it, you are, in my experience at least, going to ruin the situation and make people uncomfortable. But if you are funny and shameless enough, you can get away with murder, you can be as blunt as you want to be and people is going to to laugh it off while still giving you points for being able to correct the situation. 

When it comes to social dynamics, my experience tells me that power triumphs delicacy and decency. The times I have been myself in a situation in which someone did 80% of the talk I just said out loud something like:

'Hey! Come on! Why don't you shut the fuck up already? You are driving me crazy, I don't even remember the sound of my own voice anymore. It was masculine? I thought that it was masculine. And deep. Heavenly even. It is not? Not a little bit heavenly? You ruined me. That's what you did with that much talking. I'm now a listener!'. 

The other person may fight back or may feel bad. In the first case, you can banter a little; in the second, you just say: 'oh, don't take it so seriously, I really like you, you know that, I just want to hear what other people has to say and I'm a little bit of an asshole, everyone knows. We can still be best friends, right? What are your thoughts on betrayal, bestie?'. 

I have cultivated an image of someone who always says what he wants and who can take many jabs without feeling insulted. So people let me say anything and laugh at it while still listening to what I say. 

I have found out that the most intelligent thing in social situations, no matter how smart the other people are, is to pretend that you are rude and stupid when necessary, almost feral. I have found out that the only thing that makes you lose prestige in a social situation is to appear as someone weak that can be stepped on. 

I believe that for highly educated, highly intelligent, sensible people this is hard to accept. But it is my experience. Confidence and bluntness beats carefulness and thoughtfulness every time. And rationality is about wining, isn't it? To win, you sometimes need to act as an idiot and an asshole. 

Even if you don't have a sense of hierarchy, I can assure you that other people have it. 

I think this is an important topic. I think what's missing from this discussion is skill and kindness. Conversation is an art. Meta-conversation can be incredibly useful. Like other conversation, it won't be useful if it makes people argumentative, or uncomfortable enough to drop out of the conversation.

Everything is dependent on your role in the group and your personal style and skills. Making sure your tone of voice sounds kind and relaxed (ideally, because you really are kind and relaxed) makes most types of suggestions go better. Except if you're being ignored, and the situation is important enough to be worth stepping on some toes. Even then, I think a kind and relaxed tone is compatible with being forceful and repetitive.

Only the first example is one that I'd call a full meta-conversation, to identify the problem to be solved and who should solve it.  The others are meta in the sense that they're about communication style rather than content, but not meta in terms of solving a more abstract problem, and it's not helpful to mix the two kinds of meta.

I'm also not sure it's actually taboo - it's sometimes a little uncomfortable, but I don't think you'd be shunned or expelled from a group if you tried to address the communication issues.  You will find, in many casual groups, that some or all of the members PREFER this style, and you'll need to decide whether to join in or leave (or put up with the annoyance of a non-preferred turn-taking protocol).  But actually noticing and asking is both common and unpunished in most contexts I've seen.

Worth noting that most of these are about preferences or your subjective interpretation, not objective right/wrong. I think probably keeping in mind that you are making a meta request of the person/group to compromise toward your subjective preference of communication mode, rather than 'correcting' someone, would make it easier. Also, then you should consider that in this compromise you probably need to come halfway, cutting in more than you'd normally be comfortable with in the fast-talking-over each other situation, pausing longer in the slow conversation situation.

Also, you can hint at desire for shifting meta modes, and that's a much easier 'social move' to do and to receive than direct discussion of the issue. Hints would probably be the way to go for that last example.

Hmm, discussing an order explicitly is generally not a taboo, and after that one can make a point of order. What is probably frowned upon is selectively creating and applying a rule to a specific person, even if that person is the reason for the rule in the first place.

I would have interrupted with meta conversation in every single one of those instances. in order to make it kind I would have tried to describe why the people making the mistake were making one I didn't want them to have already known better than to make, and that I was simply explaining why I thought stepping back would be good. for the very talkative person I might have hushed a few times as they got used to changed settings, but I'd also have made sure conversation kept including them so it was visibly not a rejection. to accomplish this I would have intensely powered my interrupt to make sure I took the stage to briefly explain, say that I have a short point about format, then yield once my meta point was made. I do this frequently around non rationalists in voice chats online and it almost always goes well. if you'd like to hang out on vrchat I would be down to show rather than tell.

but overall: nah just ignore the taboo. we don't have time to respect silly taboos. just reassure people you don't think they should have known you'd feel this way and it usually goes fine.

They are not taboo. They are hierarchy-restricted and for good reason. Turning the lens inward can only be done from a position of trust and accountability. Which is why all your examples fit a "mentorship/leadership role" frame.

Democratising the right to meta-conversation could be considered taboo, but again for good reason. It empowers unknown quantities, while also diffusing responsibility.  Anything said cannot be unsaid, even if no decision is made. And a bad takes made on an individual level can be distanced by removing the leadership role, while collectively made bad takes will remain in the air in perpetuity.

So, while you might want to say all those things, the fact the feedback is people being offended, uncomfortable, embarrassed, and angry at your attempts is simply because you individually have not earned the right, and very likely by opening up the conversation to the room have extended a poisoned-invitation to those that know better than to claim it.

And arguably, the awkwardness itself is an inherent and much-needed barrier-of-entry to meta-conversations, exactly to illicit trepidation and cost-benefit analysis, preventing noise or bad-faith. As in any meta-conversation worth having, should be initiated at a cost.