Hussar
Legend
Ahh, but, see, that's where consensus building comes in. If two players want something that is incompatible with what the other wants, then it's more or less up to them to figure it out and then come back and tell me what the decision is. I'll weigh in with my 2 cents (knowing me, it's likely be even if they don't ask me.That said, in the post you quoted I'm talking more at the setting-design level - say where one player wants the setting to be on a Neo-Pagan chassis, for example, while another wants it to more reflect Christianity and the surrounding mythos; and neither really wants the other aspect in the setting. Allowing both those players any sort of authority over setting is a recipe for complete disaster.

Again, that's the point of shifting authorial power. Sure, the DM is there to break logjams and guide the conversation, but, by and large, it's all about the group finding a solution that the group is happy with. And, frankly, if the two players absolutely can't come to any sort of agreement, then me simply dictating one from on high certainly isn't going to make them any happier.
If it actually got to that point where neither was willing to compromise and their visions absolutely had to be in the game, then, well, that game get's shelved for another time and we'll play something else. I've never seen it go to that extreme though. That would be really bizarre IME. Again, that's the whole point of consensus building - knowing that just because someone gets their way this time doesn't mean that it won't go the other way next time.
Think of it from a DM's point of view. I think it's fair to say that a DM includes things in the setting that the DM thinks will be fun for the group. Or interesting. Or engaging. Whatever, a net positive in any case. Something that makes the game worth playing. Right? DM's don't usually think, "Oh, I'm going to put this in the game. Everyone's going to have a sucky time and that's great!"

Well, if everyone is a DM, then everyone has to think that way. You can't advocate for one PC or one player if you're the DM. DM's must be impartial and neutral. I think that's a point that we all agree on.
Well, if everyone has some authorial power, then everyone has to be impartial and neutral. It's in the job description.