You see, when you miss and fail to articulate a necessary distinction, it always looks like you're contradicting yourself. What they're all missing is the formal/material distinction originally articulated by St. Robert Bellarmine and masterfully applied to the current crisis by Bishop Guerard des Lauriers.
It is an unnecessary distinction or perhaps best left up to competent theologians to sort through some day.
The fact is, the hierarchy is not infallible, either in a council nor dispersed throughout the world - this idea is a major cause of confusion, particularly among sedes. Per V1, only the pope is infallible when he defines a doctrine ex cathedra.
Sedes believe LG 25 is a Church dogma - and it is a dogma - of the conciliar church, not the Catholic Church.They read "hierarchy" and "Magisterium" as one and the same, both infallible which is altogether wrong. So when they see the hierarchy spreading error, they say the infallible magisterium as defected - which is the completely wrong thinking inspired by the NO doctrine in LG 25. All it does is start debates about formal/material that has nothing to do with reality at all.