All traditions tend to become mythologized. Rousseau is lurking about somewhere here.
It is helpful to understand as much as you can about a song, a style, a tradition of music
but it doesn't follow that the performance will be better because of this. In some cases,
when mimicry or imitation is done, it vitiates whatever the performer has to say. The voice becomes as a result phony and unnatural.

I reiterate that to force a national identity on a singing style or song ignores the particulars of region, personal character of the performer, and draws unnecessary lines that obscure rather than enlighten.

The big culprit here is over generalization about what is English or Irish or any other culture. Irish music must contain elements of English and Scottish music, and the reverse is true as well. Balkan and Spanish music has found its way into Irish music which is to say that there is no pure true Irish, English or Scottish music or any other national music.
Every musical form retains historical elements from other places and past times.

This also means that to understand the history and tradition of each musical form opens
a world of enjoyment and impact on the listener and the performer.

Visiting the St. Ann's College in Cape Breton, an official scholar informed me that
Scots were "some of the biggest mutts in the world".

I think this could expand to include almost anyone from any national heritage and it certainly true of musical styles.