I'm firmly of the opinion that this kind of discussion serves no purpose. The subjects of my interest are the people who sing and the songs they sing - not some of them - all of them. I don't like all of the singers, or their songs and I only sing songs I know and like but I don't restrict myself any further - I don't say my songs are worth more than his.
However, I will say this - this argument comes about because the people who formulated the definitions which made a distinction between folk songs and other kinds didn't know enough of the facts of how things worked to be able to frame an adequate set of definitions. We may either choose to formulate a new one to accommodate all the new factors or choose not to - but if we choose not to we have to understand that there's nothing left to talk about.