Obviously it's all in the ear, all in the mind, of the beholder. No song has one concrete meaning applicable to all of its listeners.
People understand that, yet they still instinctively want to look up the lyrics, they still want to look up the interviews artist Y has done or read the story that critic Z has written, to try and fashion a knowledgeable interpretation of Song X.
Sometimes--a lot of the times--I think that I enjoyed the song, and understood the song, more powerfully *before* I read the criticism, before I found the lyrics. I think the crux of it is that your imagination can never quite encompass a song whose lyrics you're at least somewhat uncertain about. Whereas if you know all the lyrics--no matter how accomplished, your mind can then circumscribe the song.
And its all-powerful mystery has vanished for you.