Thanks for the info on SSPX. Interesting.
Regarding referring to each Protestant sect singly:
I am willing to do that when the individual Protestant with whom I am speaking will identify his sect.
Speaking from my experience over at CBBS, that is a rare occurrance. Most of them are reluctant to identify their sect, prefering to refer to themselves as "Christians."
It usually does not take too long to identify in broad terms the general category of Protestantism to which they adhere, but it is often a process of trial and error.
Another problem with treating each Protestant sect singly is that it seems to elevate that sect to a level of parity with the Orthodox Church: not an impression I want to give.
For me it is important that Protestants understand the considerable gap between their traditions, which do not have roots that extend beyond the 16th century, and the one, holy, catholic, and apostolic Church.
It is also difficult to deal with each Protestant sect singly when there are so darned many of them!
Besides that, many Fundamentalist and Evangelical Protestants are chronic church-hoppers; a particular sect is of far less importance to them than their own ever-changing, private take on the Bible.
Whenever the pastor's understanding of the Bible clashes with their own, these believers go down the road to the next "independent assembly," or better yet, rent a building and start one of their own.
Voila - a new sect is born!