The music from any one country contains many elements that give it it's own national flare, or style. I would say a song was Irish if composed by an Irishman about a current affair as seen through Irish eyes, especially written in Ireland.

I see it like the color spectrum; The solid true colors representing the music of any one country, but there being blends of the colors between the bands. I think it not surprising that non-Irish folks might want to write a song in the "Irish style". After all, you hear a style that you really like, and then want to play that style or emulate it through your own compositions.

Just my ever so humble opinion.

Margarita