"It's bleedin' obvious that traditional music is for entertaining. Arguments arise when people try to insist on their own narrow definition of what constitutes 'entertaining'."
I second the second and give a second thumbs up.
More broadly, arguments arise when people try to tell other people how they ought to play, listen to, enjoy, or introduce music.
It is bleedin' obvious that anyone who gets up in front of others and performs music is engaging in an act of entertainment. Some people are better at entertaining than others; for my tastes, the people who are on the extremes of both sides of this thread are the worst. I really don't want to hear more talking than music, and I really do want to have the songs introduced in at least a minimal fashion. "Here's a tune from Wales" is a thousand times better than no introduction at all.
And I want the entertainer to be sensitive to what sort of audience he or she is playing for and to speak appropriately. I wish that both the pedants and the silent types would spend a bit of time honing their entertainment chops while they are honing their musical chops. Some might be better in classrooms while others might find their natural audiences in comedy clubs. But in any event, they are inflicting themselves on others -- I would be thankful if they tried to acquire some skill and sensitivity before they do.
I've spent most of my life playing traditional music and there are pros and cons for different performing situations and for different levels of knowledge on the part of the audience. If I'm playing in a folk club, I'll share a lot of information about the origins and development of the music and tell about my sources and a few stray thoughts on the nature of traditional music. But the delivery of this information is as important as the information itself; if it's not entertaining then it's not, well, very entertaining. A pro for playing for a knowledgeable audience is that they already have a good idea of what I'm up to -- I don't have to explain everything to put it in context. The con is that the many members of the audience will have very specific ideas about how I ought to play music and are not shy about sharing their feelings in negative terms.
A more general audience will get a shorter introduction that tries to relate the song to the experience of people who haven't experienced traditional music before, while still being entertaining. The con, of course, is that more basic explanations are often required and some people just go away shaking their heads about the weird musicians they saw today. The pro is that they don't have pre-conceived notions about whether or not I'm playing the music correctly and they don't care if I don't tell them who I learned the song from. A big pro is that there is usually someone in the audience who has never heard anything like that before and who gets completely turned on by traditional music. That's the best part.