If art explained itself it wouldn’t be art. It would be an instruction manual.
I’ve often been irritated that I can’t discern the meaning of a lyric or the significance of a painting, yet without this tension there would be no intrigue. User manuals are the most boring literature in existence.
There’s also the tension the artist feels. Imagine laboring over a creative work and knowing that most of the meaning will be lost on those who consume the work. The temptation to over-explain is intense.
Artists have to be content with misunderstanding. Mystery enables discovery—over time our perspective changes and we see the same thing in a different light—and mystery invites interpretation. I interpret a lyric one way, you see the same one differently. If the writer said too much about it, all that juicy speculation would be over, even though part of me still wants them to.