I still maintain that the dumbest AP style rule can be found in the split verb entry, which maintains, against centuries of idiomatic English usage, that it is a Bad Thing to place an adverb between an auxiliary verb and the main verb, encouraging generations of journalists to write in that non-idiomatic and strained dialect of English called journalese.
But earlier today, a colleague mentioned on Twitter the injuries entry, which says flatly, as if from the thundering mouth of Jehovah, "They are suffered, not sustained or received.
The Oxford English Dictionary gives the sense of "To endure, suffer," and dates the first citation from A.D. 1330. Milton wrote in Paradise Lost, " This is now Our doom; which if we can sustain and bear, Our Supream Foe in time may much remit His anger." The sense of bear in sustain is very old in English.
Merriam-Webster's Dictionary of English Usage dates the skittishness about "sustaining injuries" from Henry Alford in the nineteenth century, and Jan Freeman writes that Ambrose Bierce took it up enthusiastically, even though there is no warrant for it.
What we have, again, is a superstition about usage that the editors of the AP Stylebook have preserved in amber, without regard either to historical patterns of usage or contemporary practice.
I have suggested repeatedly in these operations that writing in a variety of English that differs from the one that literate adults actually use is not the way to sustain or enlarge our audience, and, unfortunately, the AP Stylebook is sometimes an obstacle to that goal.
That melancholy fact established, I invite you to suggest your own nominations for the dumbest AP style rules, which I will make available, dutifully but without much expectation of success, to the editors.