First off the definition is too unwieldy, reflecting defining processes of its time. If there's a need to identify a 'music of a community' you might begin with something as plain as 'adopted and transformed' as key ingredients. That would included modern football songs and chants which undergo such changes, pub drinking songs (inc. popular songs) modern nonsense songs, etc.

The contradiction in one social group examining the artifacts of another was not problematic then (read any popular boys adventure novel of the period to see how 'ordered their estate' was) and there was an impulse in exclude rather than include - which it seems still goes on.
Society as a whole is more atomised than it was when the definition was drawn up and processes more immediate and proliferating. A comminity definition has to follow those changes.