It's like this - Radio, TV, Record companies, Shops, Clubs, Festivals, practically anything one can think of that decides common definitions - have come down on the side of folk being This Thing. It's loose edged what-not, a bit like jelly but even so there are few real surprises. It rarely tastes of cake let alone Lobster Thermidore.
Except on Mudcat.
On Mudcat it's an intensely problematised Thing that resembles a fine wooden box, a box with French polishing and dovetail joints. It's suggested here that traditional music is barely available having been crushed beneath a commercial hegemony of plastic boxes but is something folk woild clamour for if only it was given a little exposure.

I don't believe that to be the case. I believe that even among folk fans traditional works, presented in what the performer imagines to be an authentic way are 'difficult'. That doesn't make them wrong or bad (I loves 'em), it makes them inaccessible and that inaccessibility means they make up a modest proportion of what audiences who keep these events going will pay to watch - except of course in Lewis.
Observation leads me to further believe the debate comes down to True Believers, those who think there's a musical pyramid with the tradition on top like the eye on a dollar bill and those who keep the tradition close to their hearts without feeling it's either on top or trapped in a cellar waiting to be let out before returning again in glory (to continue the splendid religious analogy earlier).

I use the term True Believer because there's an ongoing suggestion other posters don't actually like traditional music but have had their vital faculties weakened by cheap plastic boxed from Lidl and Aldi, which is snobbery in a different hat.

There's a splendid definition of folk music above by Tug the Cox and I commend it to all those with a hole in their arse.