As a wanna be songwriter, I deny that the writer has a monopoly on meaning. Just because I wrote the song and it means something to me doesn’t mean I should impose my interpretation on everyone else. Others’ interpretations are just as valid.
Melanie Safka said she did not intend “Brand New Key” to be about sexual intercourse and I believe her. That doesn’t mean it isn’t. It obviously is.
The only exception to this rule is when you think a song is about drugs. Assuming everything you don’t understand is about drugs is just lazy.