except it's not true. an old, incorrect myth...

dago came from 'diego' and originally was directed towards spaniards. it somehow started getting said towards italians, and well....you know the rest. sometimes people also use the slur of 'guido'.

as for wop:

One famous false etymology is that it stands for "without papers" or "without passport" (abbreviated WOP),[1] widely known to be a fantasy derivation by acronym.[2] According to Merriam-Webster its first known use was in 1908.[3] The commonly accepted etymology is that it originates from a southern Italian dialect term guappo, meaning swagger, derived from the Spanish term guapo, via dialectical French, meaning ruffian or pimp.

Ok then. These are things I don't look up.

i looked it up because i knew 'without papers' wasn't where it came from. but people still repeat it, just like they still say the turns are tight at pimlico.

My grandpa commonly used 'Dago' describing everything from fellow Italians to dago food, dago t-shirts, dago garden etc.

Use or call him a 'Wop' and it was on.

NYRA Food Truck Suit
 

Another myth, this one in the form of a kind of joke:

Q - Do you know why so many Italian guys are named Tony?

A - Because the immigration officials put a tag on them when they got off the boat - To NY!