I don't recognize that there are any "sub forums", because whatever is posted anywhere shows up in "What's New" and that is the only page I really look at regularly. For any given searched subject, the search engines raid all the "sub forums" just as if they were all in one room.
Because of this great feature, I have no objection if others want to ghettoize themselves, they are only pretending that others can't see and join in. It does seem divisive at first glance, though.
I also don't believe there are any great longstanding "traditions" in fly fishing, there is not even a universal or commonly accepted definition of "fly fishing". The technology of rods, lines and tying materials changes constantly and the "sport" evolves to take advantage of it.
By Tradition many/most of us might not even be fly fishing, as up to the mid 20th century it was almost reserved to Professionals (doctors, lawyers, etc.) and the Gentry. (or maybe I'm wrong and all the rest of you are old money gentry)
By longstanding traditions only endangered or extinct birds could be used to tie the flies and we'd all have to be Club members. 150 years ago the Dry Fly Tradition would have surprised most fly fishers. 75 years ago the Sinking Line Tradition could not have existed. And so on with most of the so called Traditions. I recall seeing methods of fishing flies with bobbers in the late '50s or early '60s which is about the time frame when most of the great traditions seem to have become established. And split shot were added to fishing lines long before the invention of plastic allowed high density sinking lines or the construction of special tapers.
Who, besides myself, regularly uses a Level Line?