Because "la gozadera" comes from the verb "gozar" and means the act of having a good time, making of a good moment with friends, an even better moment with a lot of laughs, fun and sometimes music and drinks. To form a "gozadera" is a common saying from latin people of Latin America, and it s widely known that our "gozadera" (our form having or making a good time) is unique and very different from the form of the others nations of the world. Also, the way to form a "gozadera" is similar among latin nations. The fact that Equatorial Guinea and Spain are not mentioned in the song is because if well in those countries the language is spanish and Equatorial Guinea was a former colony of Spain, those are african and european countries with different habits and customs. The way to create of creating a moment of joy there, is different from the way we do it here, and certainly, they do not actually call it "gozadera". Miami and Puerto Rico are american territories but widely populated of latin people which is why are mentioned territories in the song.
