More generally, do the writing tutors of the world really think we should not report that a politician has been shot until we can specify the gunman?Unknown gunman shoots Senator X. It's really not that hard and, as by the way, lets the reader know exactly what is currently known or not known about the event. In another case, he argues:
The piece I was writing—a sad task—was an obituary. In one sentence I explained how I had met the deceased: “I was introduced to her while she was visiting California.” My helpful colleague asked: “Why the passive? What’s wrong with ‘We met …’?”—and the answer is: Nothing at all, except that it omits the very thing I was saying, namely that this was an actual old-fashioned introduction, not a random encounter in an airport bar. So I ignored that well-intended advice.If the introduction is so important: A mutual acquaintance introduced me to . . . . Once again, the reader gets all the information necessary to make sense out of the event and, surely, if an event is important enough to introduce, it's important enough to explicate fully. Passive fails to provide all the necessary information in order to fully understand, usually by leaving out agents and actors.
His big mistake, I would argue, is that he thinks that people don't like the Passive Voice because of Strunk and White, which is -- again I think, wrong. It's about short declarative sentences and imparting information. Plus and also, its usually advice reserved for papers and reports, as opposed to Obits, poetry, and novels.