Do you think that it is perfectly acceptable for a player to tell the DM, "No, you're doing it wrong"?
Isn't it? In principle, if not in specific? Or do players have to accept that a DM is always right, and not to be questioned? I know I don't. I can question a decision. I can walk out and leave. This may be unfair of me, or it may be the best decision to avoid a confrontation over something that can't be resolved.
I do the same for players too. There may be times where I'm being questioned, and it's a good thing, and times where it's a bad thing. It happens both ways.
Because, for me, that's what it comes down to. Bumbles, whether you like it or not, that's what you are saying.
Indeed, that is a basically accurate representation of my position though it may not be be completely accurate as to how I perceive it, mind you.
You are telling the DM that he has changed something about the setting that you do not personally like and that is unnacceptable. Either the DM changes the element back, or you refuse to play.
Is there something wrong with saying "I won't enjoy this" when confronted when something I won't enjoy? That doesn't seem fair to me, yet it seems to be implied.
Does it really matter where you draw the line?
Absolutely. Otherwise, I feel you're basically saying I'm not able to form a reasonably opinion, and it seems that you think that I should just obey the mantra of the "DM is Always Right" . The DM can be in the right. The Player(s) can be in the right. Accordingly, the where does matter. They could even both be in the right or the wrong.
You might think your criteria are perfectly reasonable (and I do too for that matter - I agree that your criteria are perfectly reasonable) but, I've been told over and over again on these boards, by people in this thread no less, that the DM has absolute authority over his campaign.
Well, in a sense, they do. This is met by the Players having absolute authority of where they play. It's a case of Unstoppable Force meets Immovable Object.
That a DM should NEVER allow player wishes or preferences to over ride his or her own.
A DM who takes that absolute position is one who I will probably not play with for long. Smart DMs know when they can yield one preference or wish in order to improve the game.
Why is it ok for the DM to absolutely over rule a player in one part of the setting (I don't like X so no X in my campaign) and not in another?
Why is it ok for me to go into a hamburger shop and say "Hold the Ketchup" when I order a burger, and not ok for me to ask for a Pizza*?
Because the two things are different, and where you draw the line matters.
*Of course, there are places where they can serve me a pizza, but let's not tear this analogy into pieces, it's a simplification by necessity, and not something to argue over. If it helps you understand my position better, great, if not, tell me what will.