SS keeps using this word "shibboleth" and I realised that I didn't really know what it meant - so I googled it:

"A'shibboleth'is any distinguishing practice which is indicative of one's social or regional origin. It usually refers to features of language, and particularly to a word whose pronunciation identifies its speaker as being a member or not a member of a particular group."
(Wikipedia)

Well, I belong to a group who believes that 'folk song' is a limited and definable genre and that the 1954 definition is a good guide to the limits. In my opinion the word 'shibboleth' may not be entirely appropriate in this context - but close. Nevertheless, I don't see anything to be ashamed of. I'm certainly not ashamed of the fact that the existence of that particular group appears to get up certain peoples' noses. I believe that that is the problem of the nasally afflicted, and until they can come up with something better than "folk song is anything I say it is" it will remain their problem.