"I think some kinds of music are called folk music but aren't,"

Whilst I don't disagree with much of what you say, Piers, we're back with the thorny question of 'what is folk music?'. It's one which has caused huge disagreement and which no-one has successfully answered, so I'll withdraw from that debate and hope that everyone will enjoy their version of "folk" and, hopefully, other people's, in whatever way they choose, without being preached at by the likes of WAV.