Josepp
I'm sorry to hear what a poor time you have had. I can't believe it was from folk musicians as most of them I know would not act like that. However, I believe there is a different requirement for folk music than pop etc in that with folk music you want to hear the words of any song. I think that if you get a rigg from people who are used to doing pop they may not realise this.
I also think that with ticket costs rising people expect a better quality of sound. We attended 2 festivals this year where we were critical of the sound mix in the main tents. I'm not sure that either of them had any feedback system for customers to say what they thought.
FloraG