In a collection of conversion stories put out by the coming home network, I am really stunned by how so many Protestants, as protestants, saw no reason not to slip from one denomination to another because few had (or even claimed!) any authority, but were merely associations of like-minded people.
And then there were the Orthodox Presbyterians who seemed quite comfortable with the idea of excommunication.
In our culture, people are simply not used to thinking of the possibility of one visible Church.
Exactly. Agreed. And the Devil likes to keep people confused in that way. As St. Paul said, For God is not a God of confusion but of peace.