Letting school kids choose the books they read.

The NY Times article - A New Assignment: Pick Books You Like, by Motoko Rich 8/29/2009, talks about some schools where the teachers are letting the kids pick which books they want to read and there's some discussion about whether this is a good thing or not. On the one side the students should be more motivated to read books if they pick them. On the other side, they'll just read Harry Potter.

From the article:
Literacy specialists say that giving children a say in what they read can help motivate them. “If your goal is simply to get them to read more, choice is the way to go,” said Elizabeth Birr Moje, a literacy professor at the University of Michigan. Ms. Moje added that choices should be limited and that teachers should guide students toward high-quality literature.

It isn't asked why they should be required to read fiction at all. What's the purpose? Who defines what 'high-quality' literature is?