Good words from Steven Pinker’s excellent book, The Sense of Style: The Thinking Person’s Guide to Writing in the 21st Century:
Strunk and White, for all their intuitive feel for style, had a tenuous grasp of grammar. They misdefined terms such as phrase, participle, and relative clause, and in steering their readers away from passive verbs and toward active transitive ones they botched their examples of both.
There were a great number of dead leaves lying on the ground, for instance, is not in the passive voice, nor does The cock’s crow came with dawn contain a transitive verb. Lacking the tools to analyze language, they often struggled when turning their intuitions into advice, vainly appealing to the writer’s “ear.”
And they did not seem to realize that some of the advice contradicted itself: “Many a tame sentence . . . can be made lively and emphatic by substituting a transitive in the active voice” uses the passive voice to warn against the passive voice.
George Orwell, in his vaunted “Politics and the English Language,” fell into the same trap when, without irony, he derided prose in which “the passive voice is wherever possible used in preference to the active.”
Self-contradiction aside, we now know that telling writers to avoid the passive is bad advice. Linguistic research has shown that the passive construction has a number of indispensable functions because of the way it engages a reader’s attention and memory. A skilled writer should know what those functions are and push back against copy editors who, under the influence of grammatically naïve style guides, blue-pencil every passive construction they spot into an active one.