[deadbadger]

I only wish I could up-vote this more. See also this earlier Language Log essay (http://itre.cis.upenn.edu/~myl/languagelog/archives/003366.h...), in which Pullum points out that passives occur in "Politics and the English Language" at a considerably higher rate than was typical in contemporary periodicals - Orwell couldn't follow his own advice, even as he was dispensing it.

The same goes for Strunk and White, who in the very passage instructing writers to abjure the passive, say:

"Many a tame sentence of description or exposition can _be made_ lively and emphatic by substituting a transitive in the active voice for some such perfunctory expression as /there is/ or /could be heard/."

Still, at least the guide linked in the OP has picked actual examples of the passive voice as illustrations, and concedes that there are times when it can be reasonably used (sorry, "writers can reasonably use it"). This makes it something of a rarity, even if the advice is still poor.