I don't know which song your quote refers to, but my guess is that a song was written to be the anthem of a newly formed or re-formed nation. It was unacceptable, though, because the lyrics mentioned contemporary or recent events [contemporary references] that are still controversial in that country. The song can't be used, because people cannot unite around it, rather, it causes division among the people.
I hope this is helpful,
Student or Learner