The contemplation of a final solution in Ireland makes those job advertisements, familiar well into the 1940s, "No Irish need apply", seem quite temperate.However the No Irish Need Apply advertisements would only have been familiar to the sort of people who also see fairies at the bottom of the garden. American historian Robert J. Jensen has examined this in quite some detail as has not been able to find any genuine NINA notices anywhere, as his article "No Irish Need Apply": A Myth of Victimization explains.
The fact that Irish vividly "remember" NINA signs is a curious historical puzzle. There are no contemporary or retrospective accounts of a specific sign at a specific location. No particular business enterprise is named as a culprit. No historian, 2 archivist, or museum curator has ever located one 3 ; no photograph or drawing exists. 4 No other ethnic group complained about being singled out by comparable signs. Only Irish Catholics have reported seeing the sign in America—no Protestant, no Jew, no non-Irish Catholic has reported seeing one.It doesn't seem much of a mystery to me, some cultures tend towards self pitying fantasies to explain their failiures and justify their aggression towards society as a whole and wildly exagerrated stories of persecution which don't stand up to scrutiny have occurred amongst the Irish in the USA, England, Scotland and Northern Ireland. It is in many ways reminiscent of the wave of phony islamophobic hate crimes that occurred in the USA after 9/11 which will no doubt be remembered in 50 years time as genuine events.