South Park & Books

My dad told me to watch the most recent episode of South Park, which makes fun of books and censorship and stuff. He thought I'd enjoy it, since I'm a writer.
I did find it was hilarious, but I was also thoroughly disgusted. But that's not the point.
The point is, at the end, one of the kids says something about how people like to find meaning in books, when there isn't any, they like to make up their own meanings.
The episode made fun of this tendency of people, as if it was bad, but I don't find it so. A piece of literature can have different effects on different people, depending on the person.
Example: As Orson Scott Card says in the introduction to my copy of Ender's Game, a group of gifted children wrote to him saying they adored the book and identified with Ender immensely. A guidance counselor, however, wrote saying that she hated it and it doesn't accurately portray how gifted children think (obviously, considering the other letter, she is wrong). Same text: completely different reactions.
An author writes a book. He or she does their utmost best to make the writing itself as perfect as possible, describes the setting in vivid detail, includes character arcs and prunes their plot relentlessly. But it's the reader who learns from it. Why does it matter if messages were included intentionally? All of us have things to learn, and we all learn in different ways. Sometimes a certain book will help us learn those things, but it has something else to teach others.
This is why, when I write, I don't worry too much about messages when I write (of course, I do think about it, but it isn't one of my top priorities). I believe people will find things they need to find simply because they are secretly searching for it.
I wrote an email to John about Paper Towns, and the profound effect it has had on me. (This is the second time I've read it- I didn't get as much out of it the first time). He wrote a very nice email back to me. In that email, he said that the writing and reading of a book is a conversation, and the "story isn't complete until [I] read it."
This is something I completely agree with.
As Orson Scott Card said in his introduction, "the story isn't complete until you make it your own."

Those people in South Park took that book, despite how horrible it was in all ways possible, and made it their own.
Those gifted children took Ender's Game and made it their own.
I took Paper Towns and made it my own.
I hope, someday after I'm published, someone will take my book and make it their own.

(Also: the South Park episode just goes to show how incredibly subjective the publishing industry can be).