On the basis of that's what most of the Irish I have seen are saying. I agree it's not a scientific study or anything but the protestant landowners of the XIXth century are not considered part of the Irish culture and of the Irish people.
From the impression I got (again, partial, personal bias, whatever), Irish culture (in the Republic, cannot stress that enough) is catholic and celtic, both things the authority tried to suppress after the battle of the Boyne.
Protestant is seen as coming from the colonisator, the English while Catholic is the religion of the locals.
I am not making a judgement about any other country or time period or situation, I am just describing the feeling I got from me living in the Republic of Ireland as a foreigner.
Almost more than anywhere else, history is, oh so, political in Ireland