>> All the gurning, outlandish harmonies, and dull as hell ballads of little interest effectively ringfenced the folk clubs for middle class twits. <<

So, were the working-class audiences of your day (which I suspect was some time ago) more likely to be enthused by newly-written, introspective love songs, or perhaps anti-Vietnam-war polemics? Seems to me that it was the middle classes who were interested in that kind of stuff. And what about Roy Harris, a proudly working-class singer who ran the Nottingham Traditional Music Club for years?
The above quote says much more about your prejudices than about any actual music.

>> (Martin Carthy) was appearing as a member of the revivalists - rather than masquerading as 18th century ploughboy on this occasion. <<

Are you suggesting that Martin masquerades as an 18th century ploughboy on most other occasions?