Shared fiction doesn't mean "stuff one person proposes to others". It means proposed stuff that others have accepted.
If you say so.

Frankly speaking, you are the first poster I've ever heard even use the terminology....
The GM I am talking about made a proposal. It was not accepted by those to whom he proposed it (the players). Rather, they withdrew from the game and the whole shared fiction collapsed.
I find this such an odd situation since nothing of this sort has ever happened to my knowledge nor even heard of until your example.
This is question-begging, as in you are taking as a premise that the GM has "absolute power", and then are simply reiterating that as your conclusion.
And it it is not "basic" to D&D. I've already given examples upthread that illustrate approaches to D&D where the GM is constrained in what they can say.
Not at all. I've already told you it is in the new PHB and how it "works in D&D".
1. DM narrates
2. Players react to narration
3. DM narrates results
Repeat as long as you play D&D.
It is very basic. And are any of those examples D&D? Because that is the game we are discussing, after all.
This doesn't tell us anything about what constrains that narration. I mean, it is equally true of Apocalypse World, as per what I already quoted upthread:
Apocalypse World divvies the conversation up in a strict and pretty traditional way. The players’ job is to say what their characters say and undertake to do, first and exclusively; to say what their characters think, feel and remember, also exclusively; and to answer your questions about their characters’ lives and surroundings. Your job as MC is to say everything else: everything about the world, and what everyone in the whole damned world says and does except the players’ characters. (p 109)
The fact that it is someone's job to say stuff - to say what results from a PC's action; or to say what everyone else in the whole damned world does and says - doesn't mean that their are no constraints on what they are supposed to say in doing their job.
Again, not D&D.
Yes. Thanks!
FWIW, how would you have reacted if the DM had the kobold answer your questions, but the information was either a) wrong or b) had changed by the time you acted on it? Intel is great, but it is by no means absolute or reliable. Had you acted on the intel, but things go badly, would you blame the DM again, saying they are bad for tricking you or something, say they are railroading???
It depends on the details of the play. If those things are introduced as consequences of failure, fine.
Interesting. So, if the kobold gave you
plausible information (which you players believed and chose to act on), but it turned out that information was incorrect or misleading, and in the process of pursuing a course of action based on that information, the party was killed... you'd be ok with that??
I'm not certain how else they could be "introduced" other than leading to failure during play...
How is that any different than the DM introducing the kobold not having the information you seek, or being difficult, or whatever? The ultimate end is failure and "not fun", right? The players falling for false information leading to their downfall?
If that is just the GM making stuff up to control the flow of events, then yes it's a railroad.
Again, how is this any different?
I've already shown playing the captive kobold as a low INT creature, stupid, cowardly, uninformed, scared and speaking nonsense, is an
entirely plausible way for the DM to run that NPC. Such interactions might be unfortunate and disappointing to the party, but hardly worthy of disbanding the game IMO.
@Lanefan said it was hasty: we should have waited 10 sessions. (Nearly 3 months of play.)
@Paul Farquhar said that we were disproportionate.
@Zardnaar said that we were the ****holes, not the GM.
@Lanefan didn't say it was wrong, only that he felt you acted in haste. There's a difference.
@Paul Farquhar say your reaction was disproportionate. While it is clear IMO this means they believe you overreacted to the situation, I don't feel this is them telling you that you were actually wrong for exercising your right to leave the game.
@Zardnaar calling you a-holes is a bit extreme, I'll grant you, but I've known plenty of people I think are a-holes for acting as they do, but can't deny that is their right to act that way.
I think there have been others, but they're the three I'm recalling at present.
Fair enough, but I was more looking for someone who said something like:
You were wrong to leave, you should have just accepted the DM, even if you didn't find it fun. Perhaps no one has been that blatantly open about it?
And this is the bit that baffles me - people leaping to the defence of a bit of GMing that they didn't experience, and that the only report they have of is that (i) it was terrible and (ii) it led to a group of 5 people unanimously abandoning the game.
Because for many of us nothing you've said would be anything that would compel us to act as you did?
I mean, not knowing further particulars, I have been in a situation where we've captured a creature and got nothing useful from them. It was unfortunate, certainly, but well within the narrative that made sense. I've listed reasons above why such a DM might run the encounter as they did which seem completely plausible to me and well within the realm of their authority as DM.
I mean, what would it take for you to count GMing as terrible, if that is not sufficient evidence for you?
Qualities I personally find abhorent in a DM (most apply to players as well) are:
1.
Fudging dice. If the DM calls for a roll, let the dice fall as they may. I have no qulams about my PC dying due bad luck, it happens. I do have qualms about a DM "hitting" when a creature misses, or even "missing" if a hit would finish me off. We are all subject to the dice when they are rolled-- DM and players alike. If the DM doesn't want to risk the roll, don't roll.
2.
Constant retconning. I understand sometimes things get overlooked, etc. but I get tired of it after a while. Retconning too often makes me feel like the DM doesn't understand the rules, mechanics, and systems of the game (see below).
3.
Not Knowing the Rules. I certainly don't expect a DM to memorize every rule in the books! But understanding how the game works and running it consistently are essential in a DM for me. Some of this could be inexperience, but DM's who've run games for a while I expect more from. After a certain point, you are no longer "learning the game" but should pretty much know it or be able to quickly reference it.
4.
Being unprepared. Similar to the above, an unprepared DM makes the game slow and ponderous. They end up repeating themselves while trying to think of what they should do next. I get it, life happens, etc. so once in a while I understand it, but like retconning, too frequent and it seems more the habit than the expection. In association with #3, constantly looking up (more) basic rules would also fall under this group.
Off-hand that is all I can think of. Issues of style, narration, etc. is too dependent on factors such as experience, cultural differences, life experiences, etc. for me to judge a DM as "terrible" for lacking abilities I might otherwise find good.
Now, for some people those things aren't "terrible". They don't mind a slower game, or feel the game should not depend so much on dice, etc. They might not consider such a DM terrible as I might. I hardly expect my preferences to be universal--which as I said I think is one issue you struggle with: "How can we
not see the DM as terrible in your example?!"
FWIW, I'll add that although we clearly disagree on certain aspects of this discussion, I am enjoying hearing your perspective and, even though I might not agree with you in many ways, I do understand your point of view.