Patanes translates to "jerks" or "louts". It's a strong, somewhat informal word used to describe rude, uncouth, or boorish individuals.
In the song, the lyric "Por culpa de unos patanes" (Because of some jerks) suggests that the subject of the song has been hurt or mistreated by other men. This word stands out because it's not as common as other insults and adds a specific, vivid description of the kind of people who have caused her pain, making it memorable and impactful.
"Poema" opens on a single memory — "Con olor a tabaco" ("With the smell of tobacco") and "Y un beso bajo la lluvia" ("And a kiss in the rain") — a woman who once whispered "Yo soy tuya" ("I'm yours"). Oscar Maydon turns that memory into a warning: "La naturaleza te ha enseñado a ser la presa" ("Nature has taught you to be prey"), he tells her, because most men who come near her only want her looks. He sets himself apart from them — "Ese día te comprobé / Que no soy igual que el resto" ("That day I proved to you / That I'm not like the rest") — insisting he stayed for who she is, not just her face. J Balvin steps in for the outro, trading ad-libs with Maydon and shouting out the "Latino gang," turning a love song into a victory lap between two friends.