This is the 1954 definition as adopted by the International Folk Music Council.
It has nothing to do with personal preferences or tastes, nor how successful or otherwise your club is.
It's what I signed up for when I enlisted back in the early sixties and it has never been replaced by anything resembling a workable alternative (unless you count arm-flapping and "I don't know what folk music is so I won't bother defining it").
It's what you'll find thousands of examples of in folk songs collections, from 'Folk Songs of The Upper Thames, right through to 'The Penguin Book of English/American/Australian/Canadian Folk Songs' and what has been defined, analysed, discussed and reconfirmed at great length and in minute detail in Lloy'ds, 'Folk Song in England', Buchan's 'The Ballad and The Folk', Bartok's 'The Hungarian Folk Song'......... and many other academic and introductory descriptive works.
It is by no means a perfect definition, and might well need adapting, and even re-defining, but until somebody does, it's the one were stuck with.
Jim Carroll

"Folk music is the product of a musical tradition that has been evolved through the process of oral transmission. The factors that shape the tradition are: (i) continuity which links the present with the past; (ii) variation which springs from the creative impulse of the individual or the group; (iii) selection by the community, which determines the form or forms in which the music survives. The term can be applied to music that has been evolved from rudimentary beginnings by a community uninfluenced by popular and art music and it can likewise be applied to music which has originated with an individual composer and has subsequently been absorbed into the unwritten living tradition of a community. The term does not cover composed popular music that has been taken over ready-made by a community and remains unchanged, for it is the re-fashioning and re-creation of the music by the community that gives it its folk character."