The legal standard of "narrow tailoring" is simply inapplicable. When you insist on narrow tailoring, and you also insist that the target of that narrow tailoring is anything other than Gush, you make it artificially easy to preserve Gush. More problematically, any time you insist on narrow tailoring, the remedy will be incredibly sensitive to how you define the problem to be solved. Narrowly targeting Gush Mentor and narrowly targeting Gush tokens decks as a class will produce wildly different policies despite being virtually synonymous in the current metagame. Narrow tailoring produces a tortured "reading" of the metagame (because you have to define a narrow target), and the logical alternative is not sloppy tailoring or broad tailoring but reasonable tailoring. When you insist that "the problem" be defined a single narrow way, you are insisting that all players have the same preferences in order to produce a restriction. This is obviously absurd. Instead, you should be willing to look at different points of view. If almost everyone wants Gush restricted for different reasons, it should probably be restricted even if no single reason is convincing to you personally. In that framework, the belief that you have to identify a single underlying problem (which is separate from the expressed wishes of players) and address it using the best mechanism you individually devise is clearly misplaced.
I think the fundamental element that people are trying to object to (and which is obviously an expression of preferences like all B&R criteria including metagame dominance) is that the format has become Gush-polar. Even though Gush is not a majority of finishes, and even though it is not performing dominantly by itself, it creates a metagame in which everything ultimately revolves around Gush. It is the eye of the storm.
You have the Gush decks, then you have the transparently anti-Gush decks utilizing Sphere of Resistance-style effects. In combination, they represent well over half the metagame. In this episode, you said that White Eldrazi was a good deck precisely because it is the best at attacking Mentor Gush. That should be enough to sound the alarm in the back of your mind.
Obviously, there are always going to be some set of decks that the format "revolves around". That is synonymous with saying a metagame exists. The thing to hope for in restricting Gush is not that the metagame doesn't exist or doesn't feature some decks more centrally than others. The thing to hope for is that 1) a larger number of decks are "central" to the format and 2) players enjoy the ultimate dynamic that emerges more than they enjoy the Gush dynamic.
You cannot escape subjectivity. The whole reason different formats exist is because different players want to experience different ways of playing Magic. Fundamentally, Vintage is a device for satisfying player preferences, like all formats. If the DCI listens to a select minority and is cavalier with B&R policy, this is not bad because it violates some Commandment Of The Universe, but because such a decision would contradict the preferences of most players.
As the famous saying goes, "democracy is the theory that the common people know what they want, and deserve to get it good and hard." So too with Vintage.