Haunting read but intended for whom?

The Boy in the Striped Pajamas - John Boyne

Although good and suspenseful story overall, I didn't like the approach to the theme. Younger readers - if this book was intended for them - won't understand much - if they are not familiar with the subject matter - because many things were left unsaid or misspelled. That's oftentimes alright to do for older readers and adults, they can easily read between the lines what was going on, but in this case I found it annoying, because I didn't understand the point of it. It was really hard to believe that Bruno would have been so oblivious of everything, that no one would tell him what was really going on, even Shmuel. And was it so necessary to hide and misspell everything? Maybe I misunderstood the intentions of the author, maybe it wasn't for the well-being of the younger readers, but to show how Bruno was sensitive and naive child, that much that he didn't want to repeat what he witnessed. The story will surely haunt me long after reading it, but I didn't like the style nonetheless.