Welcome, dontplaceliterature.
I, too, can see the negative implications "Rank and File" has from an 'outside perspective'. But the WT organization has used this term for decades. A simple search of 'rank and file' in your watchtower library CD will load up numerous examples. I've listed a few below.
The WTBS has used it when referencing other denominations:
W94 8/15: ‘Here come the Pentecostals (or Baptists) again!’ No. People know that such religions do not have whole families performing a house-to-house ministry. Perhaps some religious groups send some "missionaries" for a two-year stint into certain areas, but their rank-and-file members do not participate in any such ministry. Only Jehovah’s Witnesses are recognized worldwide for their zeal in communicating their message to others on every suitable occasion. And they are known for their magazines, TheWatchtower and Awake!
g86 6/8: But the Second Vatican Council changed things. The Roman Catholic Church underwent an aggiornamento, or updating, that opened the way for unprecedented heart-searchings among Catholics. Vatican II gave the green light for the publishing of additional "suitable and correct translations" of the Bible, and it instructed Catholic bishops "to give the faithful entrusted to them suitable instruction in the right use of the divine books." Thus, rank-and-file Catholics can at present obtain Bibles, read them, and compare what they read with what they have been taught.
And they've used it to refer to their own. Here's one from the W86 9/1:
Yes, it is the performer who enjoys the limelight. But when the show is over, notice the long list of credits on the screen—orchestra, conductor, sound technicians, cameramen, directors, producers, makeup artists, and many, many others. All are necessary to make the performance a success. All are supportive. A similar situation exists in the Christian congregation. Some individuals are used quite prominently, but others play rather inconspicuous roles as rank-and-file publishers of the Kingdom message. Should these ones feel, however, that they are somehow less important because they are not in the limelight? Should they be unduly disturbed if they do not attain prominence?
Here's another from Dec. 15, 1971 Watchtower:
Is that visible earthly organization eager to do that grand work? Look! The appointed elders and overseers of the congregations are actively working in that behalf. The ministerial servants of the congregations are cooperating in that behalf. The rank and file of the congregations, the dedicated men and women and their children, are taking part in the work, both from house to house and publicly. The governing body over all these theocratic congregations is whole-souled behind this evangelizing work and is making every arrangement for getting the work done within the time divinely allowed. The "faithful and discreet slave" class of today has been appointed over all the Kingdom interests belonging to the Lord Jesus Christ, and, as a faithful steward of his interests, it serves out spiritual food through the evangelizing work
And one more from a Feb. 1, 1951 Watchtower:
Those taking the lead among them must set the example, and the others must imitate them. (1 Pet. 5:1-3) These leading ministers do not engage in carnal warfare, but preach. The rank and file of Jehovah’s witnesses, being also ministers of God, copy their faithful example and peacefully preach.I'm glad you've posted on here, and just wanted to clear up any misconceptions you might have harbored from this term. It can be used negatively or as a 'matter-of-fact'. But to lump it all in one class, and assume everyone on here is using it in a negative way, would mean more investigation is needed in the WTBS's literature.
I know this wasn't the main part of your post, but it did seem important to you.....in some part, at least.