I imagine the Carthy family see accepting their awards as being for the greater good of folk music. as Dick Gaughan pointed out - the first victims of the British Empire were in fact the English people.
their folk culture and stories were supressed and written out of history.

The Carthys and Watersons have made a very sincere lifelong effort to retrieve the folksongs that would have otherwise been disregarded and discarded by the establishment. I don't think you should pick them over the semantics of the award.

it is a great achievement.