Every time I've heard the expression "¡Epa!", I've taken it to be just some kind of greeting or expressive word, similar to "¡Hola!", "¡Venga!" and equivalent to English expressions like "Hey!".
I've seen it being used by people from northern Spain and Latin America, and even some friends of mine use it regularly as just a greeting (or so I think).
However, while listening to Silvio Rodríguez the other day, I noticed that he uses "epa" here and there in his political songs, and I know that he is a well-known left-leaning figure. And while pondering on what that meant, I realized that my aforementioned friends who use this word are also left-leaning. So I wondered if maybe "epa" was some kind of "inside word" or had any kind of political connotation (like, say, "camarada"). Maybe it was used during some uprising (there were many in LATAM throughout the last century) and now it carries that baggage -- I don't really know, but I'd like to.
The DLE says nothing about political connotation, just that it is used as an encouragement word in some LATAM countries (leaving out Spain, which I find weird because it is used in Spain):
- interj. Bol., Chile, El Salv., Méx. y Perú. U. para animar.
- interj. Bol., Méx. y Perú. U. para detener o avisar de algún peligro.
- interj. Bol., Méx. y Ven. hola.
So, back to the question: does the word "epa" have some kind of political connotation? Should it be avoided by people trying to speak "neutral" Spanish?
PLEASE NOTE: This question is NOT about politics. It is about the historic and current use of a very specific word. Please avoid making political statements in answers or comments, thanks.