He doesn't. He questions the idea of the papacy as a monarchy, which the Pope was; for centuries he headed a civil state. Did Jesus intend for the Pope to head a state?
From the early days the Church used the monarchical form for its organization structure. Whether the Pope is a head of state has nothing to do with it. According to Church teachings, Jesus did intend the Pope to be the head of his Church. Given that the normal form of organization structure at the time of Jesus was the monarchy, it's a safe bet Jesus had a monarchy in mind. Also, it's hard to refute that the organization structure of the Father, Son and Holy Spirit is a triune monarchy.
I read the author's intent to be an attack on the foundation of the Church by attacking its organizational structure.
Papal infallibility has been exercised three times: the dogmas of the Assumption and Immaculate Conception of Mary were defined infallibly, but had been held by Catholics for nearly 2000 years. So, these definitions were a bit redundant.
I'm not sure how your comments about Papal infallibility are relevant. However, I had the impression that when the concept of Papal infallibility became dogma, it was intended to apply retroactively to past Papal dogmatic proclamations. It has been my understanding, however, that confusion arises because the Church has not specifically declared which past proclamations are infallible.
I do find myself agreeing with the author's historical perspective of celibacy because, in fact, it is correct.
One of the oldest tricks in the book is to throw some facts with which a reader will agree into what is in essence a diatribe.
I don't want to put words into your mouth, but would I be correct in recalling that on other threads, you have supported the end of celibacy?
No. I don't want to end celibacy.
I would prefer if the Western Rite of the Catholic Church adopt the centuries-old practice of the Eastern Rite of the Catholic Church: ordain married men, but no priest may marry after ordination and reserve the episcopacy for celibates.
How would you know what was in Jesus' mind? He never defined the structure of what is now Holy Orders. He allowed the Church to do that. There were no priests among the apostles; in fact, they didn't even call themselves "bishops." And there was constant conflict among the apostles as to who had how much authority. That even involved Peter, though no one challenged him as the "Head." Organizationally, the Church could constitute itself differently, as long as the Pope remained at the spiritual center of the episcopacy, as the first among equals.