Dick,
The answers to ALL of your questions are in the thread discussion and the symposium presentation I linked to. Your question was: "So what"? I don't get it. Do I / we need to repeat everything that was said because you didn't read / listen to it? The paper explains the rationale for the discussion itself, and the context for the "performance" (a sing-around) was an experiment to enact the research (i.e. to go beyond talking about to actually doing, to affect through feeling not just thinking). Since it's not evident where you're getting this strawman about "just one way of singing a song" nor do we have a universal baseline for what musicality or authenticity mean, your point is unclear and feels disengaged from the dialogue that was happening before you walked into the room.

Surely the working sailors were musical, and one of the points in the paper is that, were they to try to sing the modern version of "Shenandoah" with their work it, well, would not work at all. In order for their bodies to be in harmony with the song, they would have to sing it in the rhythm/meter that I have recovered. Thus it's attention to this musicality that allows us to solve the "puzzle" broach by this thread—of how "Shenandoah" has come to appear as a weird outlier among the chanty genre—and the epistemological problem of the paper: How "Shenandoah" was among the ten most attested chanties sung by working sailors while nowadays its chanty qualities are so illegible that most people don't know that.

The modern version is arguably "un-musical" so far as it fails to attend to the sort of rhythmic competence that is required of a "good" aesthetic performance by work-singers. Moreover, the sea music festival, heir to that of Mystic Seaport, is a space with probably the densest gathering of people with knowledge/experience of how chanties integrate with shipboard labor. Participants' frame of reference is composed of the actions they have done/seen done on shipboard and/or performances by such people. This is not a "folk club" culture. In short, the aesthetic is different. Your tuxedo might be aesthetically good at a cocktail party, but wear it to a UAW meeting and see what happens!

It puzzles me why you'd reserve musicality for Sir R.R. Terry's published classical arrangement, which was recorded by classical artists with no knowledge of seafaring culture and then copied naively by popular recording artists.