In addition, it is necessary to comment about ecumenism. The Apostolic See praises, undoubtedly, those who promote initiatives, in the spirit of the conciliar Decree on Ecumenism, that foster charity toward our separated brothers and to draw them to unity in the Church. However, it is regrettable that some interpret the conciliar Decree in their own terms, proposing an ecumenical action that offends the truth about the unity of the faith and of the Church, fostering a pernicious irenicism [the error of creating a false unity among different Churches] and an indifferentism entirely alien to the mind of the Council.
(Paragraph 10 of "Circular Letter to the Presidents of Episcopal Conferences regarding some sentences and errors arising from the interpretation of the decrees of the Second Vatican Council" published by the CDF, July 1966)
What is "ecumenism"? The above paragraph says that many in the Church after the Second Vatican Council had seriously misunderstood it. I recall once telling someone that part of the mission of the Ordinariate was to help to bring protestants into full communion with the Catholic Church. The response I got was, "Why would you do that? If we are all Christians just with different traditions, then there is no need for that". The key word in "separated brethren" might seem to be "brethren", but it is actually "separated". They are separated from the Church, and not in communion with the Body of Christ. That is not a neutral issue.
The letter I quoted above was published by the Congregation for the Doctrine of the Faith in Rome in 1966. That means it was only a year after the close of the Council. The very fact that it had to be published at all shows how far things had gone astray so quickly (and there are a number of other concerns that are stated in the letter that we do not have time to cover here). Notice the phrase "pernicious irenicism". The bracketed words that define what that is referring to are from the original (you can see them on the Vatican website page that displays this document). It is an "error" that creates a "false unity". Something that is "pernicious" causes great harm. Therefore, a "pernicious irenicism" refers to a false "peace" that leads souls into eternal danger.
To promote the idea that Protestantism and Catholicism are merely two different ways to practice Christianity is exactly what the CDF was aiming at condemning. Sadly, I must say that it does not appear that Rome was successful in combating this. I still meet devout Catholics who think that Catholicism is just another denomination in a sea of choices. This is why they often have no problem when their children marry non-Catholics (which the Church still says is not normally supposed to be done except in special circumstances and with express permission).
To pretend that there is a "false unity" between Protestants and Catholics is what leads to people frowning when Catholics seek to evangelize Protestants (which you should still do, by the way). I recall someone telling me that when he first visited a Catholic Church and said he wanted to convert, that the priest told him he did not have to do so since he was already a Christian, and there was no real difference between Catholics and Protestants (!). He knew that something was wrong, and so he kept searching around until he found a priest who would help him to convert.
Yes, our separated brethren do have baptism, and that is a wonderful grace. They do not, however, have all the sacraments, and therefore do not have all the grace that God makes available for us to help us toward salvation. Why would anyone want to keep their protestant brothers from receiving the fullness of grace? Protestantism has many errors in it (some of which can be detrimental to one's salvation) but it does have some truths (trinity, creation, etc). This is why it is best to view protestant teaching as a truncated form of Catholicism. They have lost some of the key elements that help us to come to Christ (and added in some things that keep people from Christ).
So, if you were not sure before, you should be sure now. Evangelize, teach, and guide people to come to Lord through His holy, Catholic Church. This means, most especially, our brethren who are protestant. They are so close to the faith and merely need to brought into the fullness of it. Help them by showing them that the amazing grace that God has offered is more than just some internal feelings; it is the fullness of the sacraments, and it involves the communion with all the Saints. They are very much like the prodigal son (I know, I was there for years) who needs to be pointed home. Let us be faithful to the Church's teaching, and reach out to those who are out of communion; without compromise.
