To Clarify i am Scottish and hold no grudges against any nation (apart from the english sports teams :P)
I agree with the point that it is a saints day and should (really) be a religious festival but i suppose the same thing can be said for Christmas and Easter etc.
But to come to my point.
Irish the same as any race have at some point been ruled and the bloodline tainted.
"In 1541, Henry went against the expressed wishes of the Pope and made himself the King of Ireland as well as England. This resulted in an increase in English immigration and settlement in Ireland."
The Norman Conquest
"At the beginning of May 1169, three single-masted longships beached at Bannow Bay, County Wexford. They had sailed from Milfordhaven in Wales, and on board were Normans, Welshmen and Flemings. Their leader was Robert FitzStephen, a Welsh warlord, and they made camp on Bannow Island, separated from the mainland by a narrow channel which has since silted up. A day later, two further ships arrived under the command of Maurice de Prendergast, bringing their numbers to around 600. They were soon joined by 500 Irish warriors led by Dermot MacMurrough, King of Leinster. A century had passed since the Battle of Hastings, when William the Conqueror had launched the Norman invasion and systematic colonisation of England. Now the Norman conquest of Ireland had begun"

So the point is that it is just nonsensical to claim that anywhere in the world that your race is pure.
P.S.
Happy St. George's day people :)