jag, I have no experience of poetry readings. However perhaps the clue is in the word "readings". Anyway,from what I have heard I would observe that poets are often not the best at presenting their work. The expected and accepted practice there is presumably rather different from that which applies to many forms of musical performance. I'm not sure they have any relevance to folk clubs.

The accepted practice in folk clubs is (or has been until recently) to sing and play from memory. This reflects traditional practice, as well as the practice in most other forms of popular music.

It is not the books themselves which I object to, it is what they represent. Far too often they indicate someone who is not really ready to perform in public. They haven't done enough work to internalise their songs or develop their technique. Some may say this is elitist, but I don't believe it is a function of folk clubs to act as support groups for people with low self-esteem. If people expect others to sit still and listen to them sing, they should make the effort to learn the skills. Folk clubs offer far more sympathetic audiences than most who will tolerate mistakes (up to a point) and they are great places to develop skills, but you have to do the groundwork.

If someone has developed the skills and can present a song well then I won't notice the book.