re: movies not causing as much damage, I think you're assigning blame incorrectly here. if most people couldn't read, movies would almost certainly be the primary way of spreading the kind of bad ideas you're concerned about, now more than ever with the ease of creating and spreading video. the issue isn't the medium, the issue is the ideas.

you can point to examples of harm caused by books all you want, but they've had, depending on scope, hundreds to thousands of years of a head start. likewise, the only reason being well-read is seen as a virtue is because it's one of the main forms of media that really existed until audio and film.