Tobias Haller has nobly saved the rest of us the trouble of explaining why the Anglican right's current attempt to seize control of the Communion is as empty-headed as its previous attempts:
The fact is, a number of member churches disagree on a number of issues. (What else is new?) What we can say with some historical perspective is that Lambeth has no doctrinal authority (yet!); the Primates may express an opinion; but dissenters both to the left and the right are under absolutely no obligation to follow or concur with the judgment either of the gathered bishops or the Primates. The Windsor Report contains recommendations that the provinces have yet to endorse or act upon in a definitive way — and that includes TEC as well as ACNA, both of whom have taken actions contrary to the wishes expressed in Windsor.
Those at present with their undergarments in a tangle display a very much "make it up as we go along" sort of ecclesiology, in which they act as if what they want is what already is. Unless and until some form of the Anglican Covenant is signed off on, the Anglican Communion remains a "fellowship of autonomous provinces and churches" without a central governing authority, and with, at present, some serious disagreements among its members.
Only those who agree to the proposed Covenant will be part of whatever new constellation emerges, and will presumably submit to whatever governance to which they have covenanted. But for the meantime they are living in the pluperfect, as the New Anglican Thing has not yet come to be. And much depends on who signs up. (I've said before, I'd welcome a little more structure to the Anglican Communion. Either that or clearly back to that "fellowship." It's this living in-between with made up rules and assertion and arrogation of authority not yet conferred that I find wearing, troubling and un-Christ-like.)
In the meantime, Diane and Mary are bishops in good standing in the Episcopal Church, and hence, in the Anglican Communion. They will be welcome where they are welcome, and rebuffed where they will be rebuffed: actions entirely within the competency of any diocesan bishop outside of Los Angeles.
Deal with it.
Put another way: People who argue that what they want to be true is true because they want it to be true, are not the ones to be lecturing the rest of us on accountability.