life lessons in picture books

When working on my book review, I had some realizations as I was working through it. I used a picture book called the "Quiet Bunny" that was a story of the journey of the Quiet Bunny finding his own "sound" in the "night song". This undeniably addresses the ideas relating to acceptance, fitting in and finding your own, but as I was reading through this I wondered would the audience actually understand this? I know we have talked about how picture books are not for a specific age and can be geared towards all different ages, but this book relies heavily on illustrations and includes sounds of animals which would cater to a younger audience. My question is, are picture books that attempt to teach some "life lesson" actually getting through to the audience? Are these life lessons suppose to be learned by the reader, or are they just suppose to be exposed to it multiple times so when they themselves experience it they can make sense of it?