No, it does not bother me. There is no one right way to read a book. (There are wrong ways, certainly: If you read Huck Finn and think it is a great defense of slavery, you are doing it wrong. But there are many right ways.)
These Q&As exist to answer specific questions from people who are usually reading the book very closely and have intertextual questions about them. I answer those questions because A. it’s interesting and useful for me as a writer to think about this stuff, and B. I hope it might be interesting and useful to some minority of readers, and C. I like to get insight into other writers’ processes and so feel like mine should be fair game.
The truth is, if the foreshadowing and the metaphors and everything else work, you don’t need to be conscious of it—and you certainly don’t need to be hunting for it. The foreshadowing will unsettle you whether you’re aware of it or not, and when the twist comes, it won’t feel like as much of a twist as it otherwise would’ve.
And metaphor (which to me is not really distinct from “the beauty of the language” that you refer to above) is just another way to build the story and its inhabitants so that it will be real and alive to you as you read it.
You don’t need to think “smoking cigarettes is a symbol for adolescents’ self-destructive impulses” to know that smoking is bad for you, and these kids are aware that it’s bad for you.
Your job as a reader is to read the book you want to read. You shouldn’t worry too much about which book I want you to read, but rest assured: I am very, very happy when people like my books and find them helpful or interesting or fun or anything other than dreadfully boring.