The book is so well known in many countries as it's part of the standard curriculum (I had to read it when I was 16), so I think the German film makers felt it needed no particular references to the story. It's right next to Animal Farm, Brave New World, and 1984.
Perhaps, Lord of The Flies is somewhere on that shelf, as well. Gosh I should go back and read all those again!
I thought everybody knew that the book the movie was based on was based on the story in the OP. We had to read the book in school (in Europe). I feel old now.