I'm not joking, Jim. In any genre there are as you say people who will argue black is white. If these things had hard and fast boundaries they wouldn't be able to argue. Of course we need rough guides and labels and a wide-ranging word like 'folk' has come to cover a wide range of possible sub-genres so we need further words to narrow things down. I would say your definition of folk and mine will be pretty close and mostly in accordance with 1954, but we are very much in a minority.

I wouldn't want to abandon our existing definitions, but we have to accept it when terms come to have a wider meaning, or bang our heads against the wall!

In 54 The IFMC put out their definition but it didn't last long before they had to change at least one of the criteria. It was purely for academics and scholars to use.