So I'm sorry sir, but that particular sort of short-hand historical portrayal which you seem to be bringing here as accurate, is too much over-simplification and blend of misidentification (leaving Republicans holding the bag) that is part & parcel of the impossibly screwed-up worldview of today's American liberals, which they both promote and further distort.
Look it up. You don’t have to believe me.
Just consider this: the Irish largely immigrated to the cities, where there was at least the chance of work, which was important given the artificially constructed potato famine and the routine elimination of Irish from their age-old farms.
Now, a lot of Irish wound up in the hills, driven to subsistance living, following the Appalachians around to Tennessee, where there was no population pressure.
Back to the issue of antiCatholic prejudice - well - Google is your friend, if you would reject my thesis.