"The book's contempt for its own grammatical dictates seems almost willful, as if the authors were flaunting the fact that the rules don't apply to them. But I don't think they are. Given the evidence that they can't even tell actives from passives, my guess would be that it is sheer ignorance. They know a few terms, like 'subject' and 'verb' and 'phrase,' but they do not control them well enough to monitor and analyze the structure of what they write.
There is of course nothing wrong with writing passives and negatives and adjectives and adverbs. I'm not nitpicking the authors' writing style. White, in particular, often wrote beautifully, and his old professor would have been proud of him. What's wrong is that the grammatical advice proffered in Elements is so misplaced and inaccurate that counterexamples often show up in the authors' own prose on the very same page."