'Dago', 'Wop' or 'Greaseball' -as an Italian-American I've been called all of that, so I feel I'm entitled to throw the word back at them. 'Them' being those who in the 30s & 40s posted rent signs that read. 'No Negroes or Italians' or anyone with dark skin.
This is the same reason Black people use the 'n' word ENDEARINGLY amongst themselves. This doesn't mean some teenage white homie from Orange County who thinks he's being super-hip is entitled to spout 'Niggah' this & 'Niggah' that.