As often happens, bad will and resistance to the truth leads to stupidity. St. Thomas taught that the intellect naturally tends to truth ... except when obstructed by bad will.
You are both at once ignorant of Church history and struggle with reading comprehension, and this is compounded by what can rightly be called a popolatry.
Honorius was anathematized by the Third Council of Constantinople, an anathema that was confirmed and ratified by Pope Leo II, who then added the explanation that it wasn't for pertinacious adherence to heresy himself but for neglect, a failure to condemn, allowing heresy to flourish and thus to be used as a tool of Satan for the spread of heresy. Honorius' failure was trivial compared to the failures of Pius XII, his failure to condemn Modernism, giving it countenance in many areas, and appointing one Modernist heretic after another to episcopal Sees. Honorius was anathematized 40 years after his death. Whether or not the same fate befalls Pius XII, if you were possessed of any reading comprehension, you'd see that I said that if Pius XII isn't anathematized then it owes an apology for Honoroius, which expression means that the Church saw fit to anathematize Honorius for MUCH less that Pius XII did. It's similar to the expression that "if God doesn't destroy the United States [or Tel Aviv], then He owes an aplogy to Sodom and Gomorrha". It's a rhetorical expression that evidently you are too dense and blinded by your exaggeration of papal infallability and impeccability to properly comprehend.
In any case, take a look again at the Cadaver synod as well, where Formosus was disinterred, condemned, thrown into the Tiber, the proceedings having been presided over and approved by another Pope, Stephen VI. But then Formosus' body somehow floated shore, and so a popular uprising removed and imprisoned that Pope. Then two subsequent Popes annulled the cadavers synod, reinterred Formosus, annd condemned Stephen VI. But then ANOTHER Pope came along, one who had voted to condemn Formosus at the original synod, and reaffirmed the condemnation of Formosus, having inscribed words of praise on the tomb of Stephen VI.
So, it's the example of Honorius that Cardinal Franzelin uses as a caution to avoid exaggerating the scope of papal infallibility.
Unfortunately, in reacting against R&R, who have effectively gutted the Church's indefectibility by reducing the protection of the Holy Ghost over the Church and the Papay to the one-or-twice-per-century solemn dogmatic definition, the SVs have exaggerated the scope of papal infallibility to the point of absurdity, and to an extent that NO THEOLOGIAN between Vatican I and Vatican II ever taught. Many popes made errors, even in the docuмents they promulugated as Pope (vs. private theologian). There was much debate about whether Honorius' letter to Sergius was meant as an ex cathedra pronouncement. Another famous case had Innocent II proclaming, in a Magisterial docuмent, that the Mass was valid even if a priest merely thought the words of consecration. St. Thomas took him to task for that error.
Finally, the SVs engage in confirmation-bias-driven appeal to authority, where they puff up the authority of docuмents they like (that promote things they agree with) but then simply ignore the ones they don't like. So, for instance, a teaching of the Holy Office clearly taught that explicit belief in the Holy Trinity and Incarnation are necessary by a necessity of means for salvation, but that doesn't stop most SVs (ignoring that ruling) from continuing to claim that infidels who believed merely in the "Rewarder God" can be saved.
Apart from the CMRI, the rest of SVs reject the Holy Week Rites promulgated by Pope Pius XII because they were defective, tainted with Modernism, etc. ... despite from the other side of their mouths preaching that Popes are infallible in doctrine and discipline pretty much every time they pass wind.
This self-serving confirmation-bias-based filtering leads to self-contradiction and inconsistency, aka hypocrisy.