Like many of us on here, I have an Irish Great-grandparent, another who was Scottish but of older Irish descent, but I also have two English Great-grandparents, one of them was part Welsh.
I don't identify myself as Irish, English or Welsh. I'm Scottish, I don't celebrate St George, St Patrick or St David, truthfully I don't really bother about St Andrew's day either, but I do take pride in Robert Burns.
I'm Scottish. The reason I'm not any of the others is that I was born here, have lived here my whole life and will probably die here. Why would I cling to some tenuous thread going back through time ? Where do you stop ? Most modern theories now believe that the Irish arrived on the island from North Western Spain and Portugal, should they adopt that nationality ? What about the travels over the centuries to get to the Iberian Peninsula ? Why not say they are Austrian or Greek ? Do we follow this nonsense until we identify which bit of the world was the location where the bag like microscopic creature that was our ancestor left the sea and decide we are all actually Chinese ?