Since I'm not a professional musician I'm not called upon to give an opinion in this realm, but I am, in a small way, a professional writer, and for many years in the real world was an tech. editor. Now my editing skills and criticism are sought out, and sometimes it is a very tricky business, when dealing with mediocrity, to not demolish possible buried talent. I do think it is important to call a spade a spade albeit as tactfully and kindly as possible. For one thing, if the writer (of anything) is sincere than only sincere honesty really counts as criticism. Otherwise, it's just your mum saying, "Oh darling, I love anything YOU do."

I work hard to give balanced criticism, to find good where there is any, but there are times when I'm reminded of Thurber's admonition that whereas a a tiny acorn may grow into a mighty oak, it is also true that a tiny mediocre acorn may grow into an oak of towering mediocrity. A whiny voice, poor instrumental accompaniment, and self-serving lyrics mean either the performer has an overblown sense of self-confidence, or is unaware of the low value of his/her offering. It seems to me if your criticism is to have real value it's important to help promote a healthy ego, while weeding out egotistm.

I got into folk music during the beatnik era, and along with many talented amateurs, there was a raft of black turtleneck sweatered "folk singers." who showed no musical promise and worse yet no emotional honesty. I didn't like them then and I don't like them now.