I think it's called "selective memory." For instance, the English and the Irish whom they dogged out something fierce on that island. Once the po' and brutalized Irish came to America, what'd they do? Well, let's just say this: what the English did to the Irish in Great Britain, the Irish did to black slaves in America. The biggest, worst Irish son of a she-dog was President Andrew Jackson. "Old hickory dog" Andy was one of richest slavers in the south. He was the architect and political force behind the Native Americans' "Trail of Tears," of which, incidentally (and history NEVER tells us of THIS fact) almost 1/3 of those on the DEATH march were BLACK - either maroons (free born blacks living first in Spanish Florida, then in the Everglades with the Seminole indians) or escaped slaves!!! Andrew Jackson was the sworn, darn near apoplectic enemy of the Black Seminoles who gained their freedom 25 years before the rest of our forebearers on the battlefield, burning 21 of the richest sugar plantations in the world and causing the largest slave uprising in U.S. History (about 400 slaves revolted and burned those plantations) fighting Jackson's army in the 2nd Seminole war (known in military circles as "The Negro War"). Even after the U.S. government was forced to sue for peace - the only other war that the U.S. has EVER had to "sue" for peace was 200 years later in Viet Nam - Jackson kept up his campaign to re-enslave the escaped slaves and put into slavery for the FIRST time, the black maroons of the Black Seminole Indians.
In fiction, well, one of the most popular books in American history is "Gone with the Wind," a novel about an IRISH slaver and his slutty daughter, Scarlett.
In American fact and in American fiction, the Irish have proved they were as brutal and immoral toward our ancestors as their English conquerors and overlords in Ireland were toward them.