Dissent from the Church's teaching is an attack on truth which is the principle of the Church's communion and common life. Which is why the Congregation for the Doctrine of the Faith, in its Instruction on the Ecclesial Vocation of the Theologian, No. 40, has this to say:
"The Church 'is like a sacrament, a sign and instrument, that is, of communion with God and of unity among all men' (LG, 1). Consequently, to pursue concord and communion is to enhance the force of her witness and credibility. To succumb to the temptation of dissent, on the other hand, is to allow the 'leaven of infidelity to the Holy Spirit' to start to work."
Pope John Paul II, in his Encyclical Letter Veritatis Splendor, No. 113, says that, "Dissent, in the form of carefully orchestrated protests and polemics carried on in the media, is opposed to ecclesial communion and to a correct understanding of the hierarchical constitution of the People of God. Opposition to the teaching of the Church's Pastors cannot be seen as a legitimate expression either of Christian freedom or of the diversity of the Spirit's gifts. When this happens, the Church's Pastors have the duty to act in conformity with their apostolic mission, insisting that the right of the faithful to receive Catholic doctrine in its purity and integrity must always be respected."
The Church is a communion of persons with the Living God, brought about by the Lord Jesus in the Holy Spirit. And, as Pope John Paul II teaches in Christifideles Laici, No. 64, "..an awareness of a commonly shared Christian dignity, an ecclesial consciousness brings a sense of belonging to the mystery of the Church as Communion. This is a basic and undeniable aspect of the life and mission of the Church. For one and all, the earnest prayer of Jesus at the Last Supper, 'That all may be one' (Jn 17: 21), ought to become daily a required and undeniable program of life and action." When we understand what is meant by the Church's communion, the words of Pope Benedict XVI make perfect sense: "..In order to remain in unity with the crucified and risen Lord, the practical sign of juridical unity, 'remaining in the teaching of the apostles' is indispensable." (Pilgrim Fellowship of Faith: The Church as Communion, p. 69, Ignatius Press).
As Dr. Dietrich von Hildebrand explains, "False irenicism is motivated by a misconceived charity at the service of a meaningless unity. It places unity above truth. Having severed the essential link between charity and defense of the truth, irenicism is more concerned with reaching a unity with all men than with leading them to Christ and His eternal truth. It ignores the fact that real unity can be reached only in truth. Our Lord’s prayer ‘that they may be one’ implies being one in Him and must not be separated from His words in John: ‘And other sheep I have that are not of this fold. Them also I must bring and they shall hear my voice. And there shall be one fold and one shepherd.’"
The Archdiocese of Boston has forgotten this truth. And as a result, the local Church finds itself polarized.
Related reading here.