I would point out that over the years many popular Irish singers or bands - pop, rock (Thin Lizzy), blues (Van Morrisson) have acknowledged an element of folk music in their background and roots. Some have recorded their version of tradiional songs (maybe murdering them - no names mentioned - but at least they tried). Paddy Moloney and the Chieftains play with anybody from any musical scene.
What's so wrong with Mr. Keating being allowed to sing with somebody who is definitely a part of the English Folk Music scene? Don't knock it - he might learn something.
Quack!
Geoff the Duck.