It is a satire about life in Cuba.
The film is filled with metaphors, starting, of course, with the plot: a former economics teacher falls in love with a trucker and leaves her crass, heartless, bureaucrat husband.
The final verse speaks about casting one's lot with the poor.
José Martí is an iconic artist whose work immortalizes the struggle for Cuban independence which explains why the song based on his poems is considered the unofficial anthem of Cuba.