Perhaps its an Irish thing rather than a catholic thing. I know one bloke who has a folk group and refuses to play Fields of Athenry - cos he says its a rebel song. He won't play Flower of Scotland either for the same reason.

Another Irishman (also a folksinger) - I met him after a funeral and he was really scandalised because a friend had had Boulavogue played over his grave.

I think maybe they are a tad touchy about songs in a way that we aren't.