Likewise, whether something is really at stake is also subjective (and not surprisingly entirely up to the GMs judgment, see the pattern)....
So when I ask a player or players 'Guys, what's at stake here?' am I saying I want the scene to happen or don't want it to happen? Am I saying something is at stake or isn't at stake?
According to you it must be one or the other. After all, it's entirely up to me, right? So which is it?
Of course the answer is: Neither. The players decide. Which exposes the falseness of your starting premise - assuming a GM with complete authority used in a dictatorial manner. You simply don't consider that in increasing the authority of the players or the group the role of the GM has to change.
The one time you come close, you suddenly duck out. What if the player says a scene matters and the GM says it doesn't. But this prompts uncomfortable questions. What is the role of the GM in this situation? Why would the GM say that? Why does the GM need an opinion?
Your answer - it doesn't matter, well maybe it does but let's ignore it. Players having the authority to say what matters in the game doesn't fit your paradigm. And yet, that's what Beliefs do. They give the players the means to say what matters, now, here, this session, and nothing in BW says the GM can say otherwise.
Starting from a false premise, over and over, is the reason you struggle with BW. Until you break out of that paradigm you're going to be stuck writing these hollow 'theoretical' critiques of a game you don't understand. Apologies if that comes across as blunt.
As JC would say, play what you like.