Rather than argue that individulas are trying to fit other forms of music under the 'folk' banner (something I've never done, incidentally) it might be useful to work out why the forms of the tradition occupy the entirety of folk for many people.

As a musical sensualist it is always form that tickles my imagination first, and history provides a context. In fact I can be seduced by all manner of politically incorrect tunes and songs if they're presented compellingly without ever wanting to inhabit the sensibility from which they emanated. I don't feel I'm alone in that visceral response, which is why for so many the form is the message.