According to The Province newspaper:
B.C. Ferries spokeswoman Deborah Marshall defended the move Friday. "The publisher of this book approached us over a year ago," she said. "Because we're obviously a 'family show' and we've got children in our gift shops, we had suggested we could carry the book if there's what's called a 'belly band,' wrap around the photo."
Marshall said that, when publisher Random House refused, B.C. Ferries chose not to carry the book.
The cover features a picture of a naked youth on a horse. The book is a fictional account of the time the philosopher Aristotle was tutor to a young Alexander the Great; it has been widely praised in literary circles.
"While some people might think it's art or appropriate or whatever, parents of young people might not think it's appropriate for young children to view," said Marshall.
The New Yorker picked up the story and now The Guardian's Alison Flood has written about it.
Judge for yourself.
When I showed this to my young son and asked if he felt it was inappropriate, he scoffed: "There's a bum in The Snowman and that's for children."