Earlier quoted context omitted.
If you distribute a zip file of the book, are you violating copyright, or is it the person who unzips it?
If you walk through the N-gram database with a copy of Harry Potter in hand and observe that for N=7, you can find any piece of it in the database with above-average frequency, does that mean N-gram database is violating copyright?
Copyright takes into account the use for such the copying is done. Commercial use will almost always be treated as not fair use, with limited exceptions.