I haven't seen the film, so this is just a general comment: perhaps books are burnt because:
a) Truly visual culture (cinema, tv etc) cannot compare with the imaginative scope of literature, Besides, it's far easier to shape 'narrative' in film, thus presenting a fait accompli for the viewer's imagination. Soaps, movies and the like are a poor reflection of literature's essence.b) The book-burning, as of old, is a typically Northern European passion: along with religious iconoclasm, the burning speaks of, at once, a contempt for civilisation and for sophisticated behaviour (introspection, the appreciation of beauty etc. Of course, the 'educated elite' (the governing authority/the priesthood etc) will still have access to books, I should imagine.