I’m learning all sorts of new things here…I knew that Catholics don’t think I am a Christian, but to find out that they don’t even acknowledge that I belong to a church?
Most interesting.
Correct. Only those communities with valid apostolic succession and priesthood (and thus sacraments) and have origins in the beginnings of Christianity can correctly be called “churches”. Now, we may refer to various Protestant and non-Protestant Christian groups as “churches” out of courtesy, but they are not apostolic “churches”. This is also why we do not share in communion with these groups.
**1398
The Eucharist and the unity of Christians. Before the greatness of this mystery St. Augustine exclaims, "O sacrament of devotion! O sign of unity! O bond of charity!"237 The more painful the experience of the divisions in the Church which break the common participation in the table of the Lord, the more urgent are our prayers to the Lord that the time of complete unity among all who believe in him may return.
1399 The Eastern churches that are not in full communion with the Catholic Church celebrate the Eucharist with great love. “These Churches, although separated from us, yet possess true sacraments, above all - by apostolic succession - the priesthood and the Eucharist, whereby they are still joined to us in closest intimacy.” A certain communion in sacris, and so in the Eucharist, "given suitable circumstances and the approval of Church authority, is not merely possible but is encouraged."238
1400
Ecclesial communities derived from the Reformation and separated from the Catholic Church, "have not preserved the proper reality of the Eucharistic mystery in its fullness, especially because of the absence of the sacrament of Holy Orders."239 It is for this reason that, for the Catholic Church, Eucharistic intercommunion with these communities is not possible. However these ecclesial communities, "when they commemorate the Lord’s death and resurrection in the Holy Supper . . . profess that it signifies life in communion with Christ and await his coming in glory."240 **
This is also reflected in the “Guidelines for Reception of Communion” that is included in the Mass booklet given out at many cathedrals and basilicas that are tourist attractions and would attract large non-Catholic and non-Christian visitors:
**
For Our Fellow Christians:
We welcome our fellow Christians to this celebration of the Eucharist as our brothers
and sisters. We pray that our common baptism and the action of the Holy Spirit in this
Eucharist will draw us closer to one another and begin to dispel the sad divisions which
separate us. We pray that these will lessen and finally disappear, in keeping with Christ’s
prayer for us “that they may all be one” (John 17:21).
Because Catholics believe that the celebration of the Eucharist is a sign of the reality
of the oneness of faith, life, and worship, members of those churches with whom we
are not yet fully united are ordinarily not admitted to Holy Communion. Eucharistic
sharing in exceptional circumstances by other Christians requires permission according
to the directives of the diocesan bishop and the provisions of canon law (canon 844 §4).
Members of Orthodox Churches, the Assyrian Church of the East, and the Polish National
Catholic Church are urged to respect the discipline of their own Churches. According
to Roman Catholic Discipline, the Code of Canon Law does not object to the reception
of Communion by Christians of these Churches (canon 844 §3). **