I wonder how similar the results of a poll of American Catholics would be.
It'd be quite different. The primary reason being in the US people who realize they don't have anything in common with the Catholic Church leave it and quite affiliating with it for inane reasons. These people in Ireland ought to do the same.
Even many or most of the atheists in Ireland are Catholic, BRTD, and have every cultural and affective reason to be so.
Based on what though? Like most of the people I know raised Catholic who don't agree with the church and aren't involved in it in any way now don't claim to be Catholic.
Based in part, one assumes, on the fact of being Irish. It might seem vaguely phyletic but considering the history of Irish culture and the place of the Church within it it does have to be admitted of as entirely different from hipsters of your acquaintance making clean breaks.
You've said that you still have some instinctively Lutheran characteristics, right? It's like that, only stronger because of the nature of the country and its history.