All Christians are Catholic in the sense that there is only one True Church, even if they deny it.The Church instituted by Christ that can show apostolic Succession from the time of Christ’s walking on this earth till now is the only “Church” that exists.
It is no different than an angry child telling his parents that they are no longer his parents. No matter how much he may deny it, they gave birth to him and they are his Father and Mother.
One is not a Christian without the Sacrament of Baptism. Baptism brings one into the adopted family of God. An infant can be adopted into God’s faimily just as an infant can be adopted into any family. It does not take understanding or reason: only love on the part of the ones doing the adopting.
Later, the child must make the descision to be “in full Communion” with the Holy See; the Magesterium. This is where he makes the statement that he accepts and believes all that the Church teaches.
I pray that our Catholic family; those in full Communion with the Bishop of Rome, and those who are separated, will all reconcile and come together to receive God’s most wonderful gift of Himself at the Altar of infinite Love in the Most Blessed Eucharist. Amen.
Peace to all.