I just looked up the lyrics to the songs you sang. There's nothing in them to suggest that "the Irish are all thick navvies".

Whereas it's impossible to claim that, in the case of the "Sir Hugh" song, the "Jewishness" of the bloodthirsty character is circumstantial.

if you want to compare the two, well in the first instance it's dealing with a situation of emigrant manual labour rooted in fact - a significant part of Ireland's *actual history*.

Whereas the other just repeats an old myth about Jews being unnatural bloodthirsty monsters. Buried in Sir Hugh (Jew murders little boy; the truth posthumously comes out via supernatural means) is the "Christ Killer" idea (Jews responsible for the death of Jesus; Jesus rises from the dead via divine power)