The Irish as a group were not the earliest, to be despised. There were the English Catholics of Maryland, whose Freedom of Worship law was later overturned by the "nativists". While religion was often involved, wrt immigrants, job competition & not wanting poor folk around & were also a major factors, as well noted in "Grapes of Wrath".   

If one wants to play the old tattered "victim" card, to demonstrate your "white" but not in the "white privileged class", look how far old Irish Joe Kennedy came, & how he got back at the House of Morgan, when the SEC was created.