It would certainly explain this.
For those who don't like to click scary links (or if Slate crashes your computer), the author of the article is insisting that adults should be ashamed of reading books written for children and teenagers. They're wasting all that reading time! And they're putting themselves back into an immature mindset! And...umm...IT'S FOR CHILDREN YOU'RE NOT ALLOWED TO READ IT.
That more or less sums up her arguments. We are supposed to adhere strictly to our own age group, and never learn or understand anything about any other age group.
Anne at Modern Mrs. Darcy wrote a fantastic rebuttal, complete with quotes from several very smart authors I like, but I will just add on my own comments.
1.) It is good for us to remember our own childhood and adolescence. Whether or not we have children ourselves, we still have to interact with those age groups. An adult who forgets what being young was like will start acting like, say, Robert Lupo, who tried to hold back seniors' diplomas for throwing their graduation caps, because GRADUATION IS VERY DIGNIFIED and SOMEONE COULD GET HIT BY A HAT; thereby making an ass of himself and bringing down the mockery of thousands.
2.) Just because a book is written with younger people in mind does not mean it will not contain anything of value. This is the kind of book snobbery that turns many people off books entirely. We are not robots. We do not learn things in a simple, linear fashion-this lesson at age 5, this one at age 10, this one at age 15. You are now 18, congratulations! You don't need to hear any of those lessons ever again. Just like how school will reiterate past lessons before beginning present lessons, we still sometimes learn something new or recall something old when reading these books. Even without inherent life lessons in mind, many books written for or marketed toward children are still well-written and charming stories. It is perfectly acceptable to read something for mere pleasure.
3.) The market often chooses which age group a book is marketed toward. The Hunger Games is considered a YA novel, yet if the characters were adults rather than teens it would most likely have been placed on the adult horror or sci-fi shelves. This goes hand in hand with "genre snobs" who believe that genre fiction is somehow less valuable than literary fiction. In the end, it shouldn't matter how the market or people class a book. If it is a good book, and you're enjoying that book, read it. And don't feel ashamed.