In case I haven’t made it clear enough in posts below, “purity” of doctrine vs unity of the Church is not a Catholic option. It is a “both/and”, as is so often the case in the Catholic Church, rather than an “either/or” as is so often the case with our Protestant brethren and sistern.
Why do protestants have a difficulty with this? Because they do not have the assurance that what their Church teaches IS and always WILL BE pure doctrine. Therefore, they must always maintain the freedom and the right to “opt out” of any relationship of communion which (in their judgement) might entail them being associated with “impure” doctrine.
Whereas Catholics have the assurance of the infallibility of the Church and hence maintaining unity is a matter of receiving with gladness the pure doctrine of the Church and maintaining pure doctrine is a matter of remaining within the unity of the Church’s universal communion.
Here again, and at length, from the same talk by the Holy Father in the US to leaders of the other Christain communties:
For Christians to accept this faulty line of reasoning would lead to the notion that there is little need to emphasize objective truth in the presentation of the Christian faith, for one need but follow his or her own conscience and choose a community that best suits his or her individual tastes. The result is seen in the continual proliferation of communities which often eschew institutional structures and minimize the importance of doctrinal content for Christian living.
Note the way the Holy Father speaks about unity in fellowship and in doctrine IN THE SAME BREATH!!!
Even within the ecumenical movement, Christians may be reluctant to assert the role of doctrine for fear that it would only exacerbate rather than heal the wounds of division. Yet a clear, convincing testimony to the salvation wrought for us in Christ Jesus has to be based upon the notion of normative apostolic teaching: a teaching which indeed underlies the inspired word of God and sustains the sacramental life of Christians today. Only by “holding fast” to sound teaching (2 Thess 2:15; cf. Rev 2:12-29) will we be able to respond to the challenges that confront us in an evolving world. Only in this way will we give unambiguous testimony to the truth of the Gospel and its moral teaching.
Thus, on the contrary, orthodox doctrine is aimed at HEALING the wounds of division, NOT exacerbating them.
…I am confident that – to borrow the words of Father Paul Wattson – we will achieve the “oneness of hope, oneness of faith, and oneness of love” that alone will convince the world that Jesus Christ is the one sent by the Father for the salvation of all.
Oneness of faith and Oneness of love, Truth and Love together, make for the true life of the Church.