Huh?

From the Guardian:

It's a big turn around in terms of what is acceptable. Just a few short years ago, while teen sex had long been OK-ed and drug use was creeping in "for authenticity", death was cited as the last taboo. Now, death seems to positively stalk children's books, with characters confronting the grave with sometimes alarming abandon.

Death, a taboo in children's books?  Since when?