I have been told several times, by both students and linguistics-faculty members, about writing instructors who think every occurrence of “be” is to be condemned for being “passive.” No wonder, if Elements is their grammar bible. It is typical for college graduates today to be unable to distinguish active from passive clauses. They often equate the grammatical notion of being passive with the semantic one of not specifying the agent of an action. (They think “a bus exploded” is passive because it doesn’t say whether terrorists did it.)
The treatment of the passive is not an isolated slip. It is typical of Elements. The book’s toxic mix of purism, atavism, and personal eccentricity is not underpinned by a proper grounding in English grammar. It is often so misguided that the authors appear not to notice their own egregious flouting of its own rules. They can’t help it, because they don’t know how to identify what they condemn.