The essay is worth reading. I agree with almost everything she says --- until the end. She points out that what makes a book good or bad is frequently a question of fashion and taste, and there is real pleasure in reading "bad" books. But then she adds:
Also I read heaps of appalling sexist crap growing up and it was, if anything, a spur to my feminist politics. Thank you, crappy books of my youth.
The thing is that books do influence how people think. Oh sure, as her piece points out, one book isn't going to harm someone. In fact, many, many books won't either. And I have full confidence that the overwhelming majority of people know the difference between a story and real life (kids included). Just 'cause someone likes to read about sexy vampires doesn't mean the person is going to go off and start sucking people's blood.
But books are part of the ongoing conversation we have in our society about how things work, how they should work, how they shouldn't work, and life in general. Fiction as much as nonfiction.
As Justine herself pointed out not so long ago, how we represent people in fiction tells us a lot about what society thinks of them. And the audience hears this, loud and clear --- whether it's children of color being told that white kids are prettier and have more interesting lives, or girls that boys are smarter and girls gotta be sexy to get one.
So by all means, let a kid read books with female characters who have little agency and who spend the whole book mooning about some boy. But when someone points it out and yells sexism, applaud. And when the reader responds to the criticism by rolling her (or his) eyes and saying, "Well, I know that," applaud even louder. Because it means that the conversation is continuing, and the reader is hearing more than one side.