I. The catholic or universal Church, which is invisible, consists of the whole number of the elect, that have been, are, or shall be gathered into one, under Christ the Head thereof; and is the spouse, the body, the fulness of Him that fills all in all.[1]Totally agree with this. At the same time, this can happen within the church and denominations as well. I took issue with you not recognizing that, by definition at least, a person who claims to be Catholic is also Christian. sure it's more Han just saying it. It's more than just sitting your butt in a pew. You have to believe in your heart that you are a sinner in need of a savior. Many believe this outside of the church. But I would be willing to bet my entire fortune that many within the church, denominations even, also believe this, as a direct result of their time spent in the church. To say what you said rubbed me wrong.
That is all.
II. The visible Church, which is also catholic or universal under the Gospel (not confined to one nation, as before under the law), consists of all those throughout the world that profess the true religion;[2] and of their children:[3] and is the kingdom of the Lord Jesus Christ,[4] the house and family of God,[5] out of which there is no ordinary possibility of salvation.[6]
III. Unto this catholic visible Church Christ has given the ministry, oracles, and ordinances of God, for the gathering and perfecting of the saints, in this life, to the end of the world: and does, by His own presence and Spirit, according to His promise, make them effectual thereunto.[7]
IV. This catholic Church has been sometimes more, sometimes less visible.[8] And particular Churches, which are members thereof, are more or less pure, according as the doctrine of the Gospel is taught and embraced, ordinances administered, and public worship performed more or less purely in them.[9]
V. The purest Churches under heaven are subject both to mixture and error;[10] and some have so degenerated, as to become no Churches of Christ, but synagogues of Satan.[11]Nevertheless, there shall be always a Church on earth to worship God according to His will.[12]
VI. There is no other head of the Church but the Lord Jesus Christ.[13]
http://www.reformed.org/documents/wcf_with_proofs/