And even if they're not both right, the one who's wrong is not necessarily anathema.
You're missing the point -- the point is that if I speak from a spirit of pride and tell someone, "The Holy Spirit has told me you are wrong!", I am not only lying, I am actually committing an act of blasphemy because I am making the Holy Spirit seem to be contradicting himself. Dragging the Holy Spirit into a theological debate to score debate-points is playing with spiritual nukes... someone is definitely going to get hurt (Isa. 48:11, Acts 5:1ff, etc.)
Firedog is trying to cast doubt on the idea that God the Holy Spirit can regulate the church without some kind of human administrative order, but we already have the clear example of the first-century church... God is completely able to keep order in the household of faith. Does God usually do this through the bishops? Obviously, yes, that's why Jesus founded the church. Nevertheless, God's hands are not shackled, he has no obligation of any kind to go through the church. And when the church itself is producing carnal fruits, why would God work through the church in the ordinary way in order to correct her? It makes no sense. Rather, God presses down upon the church with the same kind of insuperable power as he did upon the Israelites: listen, or be punished, and if you still won't listen after being punished, you will be scattered and utterly destroyed. That this is the way God works in the world in both the Old and New Testament ages is clear from the seven letters in Rev. 1-3. None of us gets to "make it up as we go", regardless of our historical, political, natal, familial, tribal or ecclesiastical pedigree.
We are all, alike, creatures before God and whatever distinctions God has determined to confer upon sinners in the church, he will do so of his own accord and by his own determination, he does not need an administrative rubber-stamp from "the bishops", let alone "the Pope". The only men who ever negotiated with God (Abraham, Moses, David, etc.) did so as wretched curs hanging on for dear life against the blistering presence of God's holiness, begging for mercy not only for their own sins, but also for those of their people. They were not autocrats, they were not sceptre-wielding "popes" or authoritarian bishops handing down hierarchical "authority" from "above". God has a magisterium, but the magisterium of this Age is purely provisional and probationary... we are God's people
if we obey,
if we believe,
if we produce the fruits of repentance, and so on, and so forth (compare Deut. 28 with Romans 11:21). Anyone who is not converging on these foundational truths about who God is, does not have the Holy Spirit, they are speaking from carnality, they are simply playing church, they are no true bishop or congregant, no matter their pedigree (Matt 3:9, Luke 13:28).