When in Rome, do as the Romans do—unless that involves a form of physical mutilation, that is. The speaker and her friend are visitors to this country, on a human rights mission. If the differences between the United States and El Salvador weren't glaring enough, the visitors are young, innocent, liberals who have entered a veritable lion's lair. The list of furnishings and accoutrements might lull you into believing that "The Colonel" is a travel diary entry, but simmering below the surface of manners and propriety—remember you're a guest in their country, children—is something so other that it's nearly inhuman. And let's not even talk about the degree of objectification and dehumanization necessary to be able to inflict such atrocities on a group of your own countrymen and -women for their politics.
The colonel is only giving his guests what he thinks they have come for: brute violence. The ears are the final course of the evening and, in a twisted way, are a sign of his continued hospitality.
One reason this poem feels journalistic is the distance the speaker takes from its subject. It's this otherness or alienation that empowers most of her observations.