Objectionable Teachings ...
For some of these I agree that the Catholic Church has overstated her case in very abstract, lofty terms. But in doing so it opens the door for serious criticism.
The Catholic Church is divided within while the Protestant denominations (and non-denominations) are divided without. Examples of varieties of Catholics ...
The Catholic Church interprets the parable of the wheat and the tares to refer to the fact that church leaders (and other Catholics) who are corrupt are still members of the church...
He that soweth the good seed is the Son of man; The field is the world; the good seed are the children of the kingdom; but the tares are the children of the wicked one; The enemy that sowed them is the devil; the harvest is the end of the world; and the reapers are the angels. (Matthew 13:37-39)
How can the children of the devil lead the church into truth? The other parables in this extended section of Matthew seem to address the topic of the need for Christians to bear fruit, that Christians are to be holy and not corrupt.
The following verse is often used by Catholic teachers to claim that we need the teaching magisteriumof the Catholic Church to guide us because the scriptures are hard to understand. But that is not what this passage says. It merely says that people who are unlearned and spiritually unstable misinterpret both the scriptures [the Old Testament] and Paul's letters to support their false notions that they don't need to live virtuous lives.
Wherefore, beloved, seeing that ye look for such things, be diligent that ye may be found of him [Jesus] in peace, without spot, and blameless. And account that the longsuffering of our Lord is salvation; even as our beloved brother Paul also according to the wisdom given unto him hath written unto you; As also in all his epistles, speaking in them of these things; in which are some things hard to be understood, which they that are unlearned and unstable wrest [distort], as they do also the other scriptures, unto their own destruction. Ye therefore, beloved, seeing ye know these things before, beware lest ye also, being led away with the error of the wicked, fall from your own stedfastness. (2 Peter 3:14-17)
Certainly it is true we need guidance in understanding truth. But how can we believe that Catholic leaders who are corrupt, lukewarm in their faith, unholy, or who are not even Christians at all can guide us into truth? It is unthinkable.
From Dei Verbum (the Word of God) of Vatican II ...
But in order to keep the Gospel forever whole and alive within the Church, the Apostles left bishops as their successors, "handing over" to them "the authority to teach in their own place."
But how is it possible to preserve truth by teaching error? Examples: Arianism, absentee Bishops, "bad" Popes and Bishops. We should not follow the teachings of these.
The handing over of teaching authority implies that these teach truth. Those who do not teach truth are not valid bishops. The ideal is that all bishops have valid teaching authority but the practice is that some (many) throughout history and into modern times do not have this authority because they are "bad" bishops.
This tradition which comes from the Apostles develop in the Church with the help of the Holy Spirit. For there is a growth in the understanding of the realities and the words which have been handed down. This happens through the contemplation and study made by believers, who treasure these things in their hearts (see Luke 2:19,51) through a penetrating understanding of the spiritual realities which they experience, and through the preaching of those who have received through Episcopal succession the sure gift of truth.
There are three errors expressed in this passage ...
Keep watch over yourselves and all the flock of which the Holy Spirit has made you overseers. Be shepherds of the church of God, which he bought with his own blood. I know that after I leave, savage wolves will come in among you and will not spare the flock. Even from your own number men will arise and distort the truth in order to draw away disciples after them. (Acts 20:28-30)
Paul exhorts the bishops and priests to properly fulfill their proper mission and role. The Holy Spirit has made them overseers of the church, but when they fail to do this job Christians and their knowledge of truth will suffer.
The following passages from the Catechism of the Catholic Church seem to assume the Catholic Church is the same as the Jewish community of the time of Jesus. This is certainly not the case.
During his public life Jesus not only forgave sins, but also made plain the effect of this forgiveness: he reintegrated forgiven sinners into the community of the People of God from which sin had alienated or even excluded them. (1443)
The error of the Catholic Church is in considering herself the only valid expression of the community of God.
Men who believe in Christ and have been truly baptized are in communion with the Catholic Church even though this communion is imperfect. (Para. 3)
This says, in effect, that all Christians are Catholic. But the pope and bishops have no authority to excommunicate Protestants. The error can be reconciled by stating it this way: The one holy, catholic, apostolic church of Christ is composed of many Christian communities including Catholic, Protestant, and Orthodox. Because of the historical realities, only the Catholic and Orthodox churches have correct teaching regarding dogma and morals — the Protestant churches came about too late to provide anything other than corrective guidance.
The Pope, Bishop of Rome and Peter's successor, "is the perpetual and visible source and foundation of the unity both of the bishops and of the whole company of the faithful." "For the Roman Pontiff, by reason of his office as Vicar of Christ, and as pastor of the entire Church has full, supreme, and universal power over the whole Church, a power which he can always exercise unhindered." (882)
These statements from the Catechism of the Catholic Church are idealistic in the extreme. Certainly the "bad" popes could not fulfill this (and there were plenty of those) unless we are limiting the meaning of the word "church" to the political, material, secular arena (and even in this regard some of the popes did a poor job).
Once the church started electing "bad" popes the office of the papacy was ruined forever. The papacy no longer provides unity for the whole church, even the Eastern Orthodox churches agree with this.