On the other hand, I listen to Kate Rusby's songs and they please me very much. I get pleasure from listening to them and any thoughts of whether or not Ms R's treatment of a given song is 'true folk' are far from my mind.
The only slightly controversial thing I have to say is that, in my opinion, people should abandon this 'folkier than thou' attitude and just listen to the music they like.
If I decide that, for example, 'Long Haired Lover From Liverpool' is a valid 'folk song' then I will stick to that opinion come what may.
But it's quite astonishing to me that people just can't (REALLY can't) understand that you either like something or you don't and that attempts to change your likes or dislikes are doomed to failure.
For God's sake, that is exactly what liking, or disliking, something is all about. It's your own preference.