Hi, Bruce -
Let me see if I can't help you out with this. Firstly, we can't paint all Protestants with the same broad brush when it comes to anything. And this subject is the same.
The older mainline denominations like:
- Methodist, and
- some Lutheran
actually do name their particular parishes after Saints.
Probably not as frequently as we do. But they do. These denominations retained more traditional worship or liturgy. They tend to celebrate sacraments, more often than others, even if those sacraments aren't valid.
Denominations that came out of a stricter reform tradition of John Calvin, (i.e. the Baptists, Congregationalists, and Evangelicals) tend not to use Saints names for specific parishes. Charismatics and Pentecostals, although they come out of the Holiness Movement, which has its origins in Methodism, crossbreed with Evangelicals, with more focus on the Holy Spirit, so they dropped the use of Saint's names for parishes.
Now as to religious orders, with the exception of maybe a few High Church Anglicans, they don't have any so they don't understand the concept.
Remember Protestants confuse practice, disciplines, and doctrine so if a particular set of Christians develop a slightly different spirituality or spiritual focus, such as would happen with one of our newly forming religious orders, they are often likely to start a new denomination hence, in reality, they are the ones guilty of violating Paul's admonition.
Paul was talking about schisms in the Church, not necessarily talking against communities that identified with a particular Apostle or Apostolic Successor. His point was, whether you were schooled by Peter, Paul, or Apollos, you should all be part of the One Church, with One Doctrine, and One Faith.
It's a historical fact that in the early Church, various communities developed slightly differently, according to their specific Apostolic Tradition. That's part of the reason we celebrate over twenty liturgical rites in the Church.
But the best way to explain religious orders or communities within the Catholic Church is to focus on the gift, calling, or spiritual focus of the Founder, or the person the order is named after. The members of these religious orders, have the same calling and believe they have been called to continue the specific spiritual work of the founder or namesake.
A Paulist doesn't have a different doctrine than a Carmelite but they are called to a different work and have a different gift. A Paulist is called to spend the bulk of their mission evangelizing, whereas a Carmelite is called to prayer and contemplation.
Evangelical, Charismatic, Pentecostal, and non-denominational Christians actually do the same thing and can relate to this . . . if it's explained in terms of the gift and calling. They will recognize that some are called to and gifted to spend their time evangelizing or being prayer warriors. They will also recognize that some are called to service . . . as in serving the poor . . . just as we have the Missionaries of Charity or certain Franciscan orders.
As I said, sometimes our Protestant brothers put such an emphasis on (discipline, practice, or calling), that they confuse it with (doctrine) and start up a whole new denomination. Evangelicals, although the term encompasses many denominations, actually became a denomination, as an offshoot of fundamentalist churches. Sometimes it was a reaction or response to the fact that the denomination had stopped focusing on evangelization.
So the first thing you want to do, is get the person you're engaging to understand that Paul, is really talking about schisms within the Church. He was also addressing a certain amount of spiritual pride by the followers of certain founders. His issue wasn't what the schisms were called, but the fact that there were schisms.
Today Paul might be correcting all the Protestants for the denominations:
- the Baptists
- the Congregationalists
- the Assembly of God
- the Church of God
- the FourSquare
- the Lutherans
- the Calvinists, etc.
I hope this helps,