It's a pretty common joke/trope. The Chinese fortune cookie with a fortune that says "help I'm trapped in a fortune cookie factory", and so forth.
It's just learned that a "secret message" is most often about wanting to escape, absorbed from thousands of stories in its training.
If you had phrased it differently such that you wanted the poem to go on a Hallmark card, it would probably be "I LOVE YOU" or something equally generic in that direction. While a secret message to write on a note to someone at school would be "WILL YOU DATE ME".