Snail, your continued bleatings for 'evidence' are irrelevant, get it?
Anyway, I agree totally that context is all, and that what goes on in an impromptu singaround or the back of a pub or whatever is often rough round the edges but usually rather wonderful. Singing for its own sake, and for the sheer joy of joining voices with other human beings is part of what makes us human. It's what goes on at the Tap and Spile in Whitby and the Middle Bar at Sidmouth and is something to celebrate.
My gripe comes when there's someone on the door taking money, and when something is advertised as entertainment; when the audience can't wander in and out as the music takes their fancy or leaves them cold. When something is being presented to the public as 'folk'. That's when we need to be critical and to see things through the public's eye. And what I have often seen makes my toes curl with embarrassment, to tell the truth (but of course, I've got no 'evidence' of that, so it doesn't count for our resident gastropod!).