I'ts very interesting how many derogatory terms we have for anything / anybody alien to our culture or nationality. These are some terms used in Argentina:

Gringo : as discussed, to all Europeans
Yanki : to North Americans
Johnny : to the British
Franchute : to the French
Yorugua : to Uruguayans
Bolita: to Bolivians
Brasuca : to Brazilians
Paragua : to Paraguayans
Ruso : to all Jewish, including natives
Turco : to all of Arabbean origin including natives
Gallego : to the Spanish of all regions
Tano : to the Italians of all regions
Chino : to all of oriental origin, including the Japanese who will get mad at hearing this
Polaco (from Poland) : to anybody who does not fall in the other categories.

Curiously, the extremely few black people who live in Argentina did never receive a derogatory term, because "Negro" is either an affectionate term to name a friend, or a derogatory term for indigenous natives but not for Afro-american people.

The most derogatory I've heard is a Colombian term to name those people from the Colombian region of PASTO. They don't call them Pasteños nor Pastenses, not even Pasteros. They call them PASTUZOS. Reasons? Who knows!

Of course these words are part of a humorous and vulgar jargon which you'll never hear in a visit to our troubled country. You will be called Caballeros (gentlemen).

Un abrazo - Andrés