Granted, If I remember correctly it was advanced level. Book 6? Though people back then must have thought memorizing everything and reading books written in the language you want to learn is the main way to teach the language. This was before people decided there must be other ways to learn it.
Yes, poetry is on a whole 'nother level, which aside from the figurative language, must be hard if there are a lot of nuances and cultural tidbits inside. (Watched some few videos on Kpop lyrics, which might be a bit different, but them being explained, the history, puns and wordplay packed in some would really be lost on a non-native speaker after a shallow listen)
Also, googled a few Puerto Rican documents to see how they look like. 
