"Please don't tell me that I must follow the somewhat vague standards of the 1954 definition in order to "undertand" and thoroughly appreciate the songs and tunes I sing and play, because that truly is utter and complete balderdash."

'Rifleman', no-one is telling you to do, or not to do, anything! Sing what you like, and "thoroughly appreciate" what you like, but if you sing recent pop songs (or jazz standards, or operatic arias, or Victorian parlour ballads etc., etc.) in a folk club, and I'm in the audience, don't expect me to greet your efforts with much enthusiasm.