I don't say that. The Church is free on the authority of Christ to teach on whatever subject she wishes to teach. The Church in fact has an obligation to teach on matters that are important for our salvation today, such as war and peace, the rights of the unborn, limits of science, etc. None of that were issues in front of the early Church, and hopefully the future generation will consider our battles won and done with one day.
Your post betrays another false supposition: that the Church would teach whatever is expedient. We are against the scripture being the rule of faith because it is not. We could easily say that veneration of Mary and the saints, for example, comes from the scripture. But that would be false doctrine: the scripture is not a source of the teachings of the Church, but rather, the scripture is one product of the Church's teaching authority given her by Christ.
The hostility you precieve is the hostility to deception. I am hostile to the Protestant heresies because I love the Truth. I am especially sorrowful when I see the Protestants pretend that they respect and follow the Holy Scripture that I love, when in fact their foundational doctrines violate the scripture.
The Catholic claim is that the Scripture being a part of the revelation given the Church, the entirety of that revelation is consistent with the scripture. But there are parts of the revelation that are later conciliar teaching, absolutely, such as perpetual virginity of Mary or the wrongfullness of abortion, that do not directly derive from the scripture.
“But there are parts of the revelation that are later conciliar teaching, absolutely, such as perpetual virginity of Mary or the wrongfullness of abortion, that do not directly derive from the scripture.”
8Watch yourselves, so that you may not lose what we have worked for, but may win a full reward. 9Everyone who goes on ahead and does not abide in the teaching of Christ, does not have God. Whoever abides in the teaching has both the Father and the Son. 10If anyone comes to you and does not bring this teaching, do not receive him into your house or give him any greeting, 11for whoever greets him takes part in his wicked works. - 2 John
26Therefore I testify to you this day that I am innocent of the blood of all of you, 27for I did not shrink from declaring to you the whole counsel of God. 28 Pay careful attention to yourselves and to all the flock, in which the Holy Spirit has made you overseers, to care for the church of God, which he obtained with his own blood. 29I know that after my departure fierce wolves will come in among you, not sparing the flock; 30and from among your own selves will arise men speaking twisted things, to draw away the disciples after them. 31Therefore be alert, remembering that for three years I did not cease night or day to admonish everyone with tears. - Acts 20