Well, compared to Tolstoy, HP would be a walk in the park. BUT as the article pointed out, it's not just HP that is being offered as lit in the schools, but the Princess Diaries - wonder what else.

At our HS, the kids are still required to read the classics (and some newer works that are equally difficult), much to their chagrin. When they pick a book for a book report, it's usually something lighter. I'd hate to think about a life without the folks from the classics. I don't remember Jack London being particularly difficult reading. It's the middle of the night. I'm sure there were others.

No one that I know ever claimed HP was difficult reading.