Difficult as it must be to endure challenges to what the stylebook says, it must be doubly troubling to be challenged over something the stylebook doesn't say. That's pretty much the case with the verbs entry, in which the advice that a split is sometimes "necessary to convey the meaning" attempts to weasel out of an indefensible absolute stand.
There is also something inadequate about the who, whom entry that could be readily remedied,* and, once again, I step forward with a humbly helpful suggestion.
The entry opens, "Who is the pronoun used for references to human beings and to animals with a name," and that is fine as far as it goes. But it tacitly offers aid and comfort to the misguided souls who imagine that who is the only option in referring to people, that that is illegitimate.
Merriam-Webster's Dictionary of English Usage traces this crotchet to the eighteenth century, an era when many grammar books appeared to assist the rising middle class in becoming respectable, meaning more like Latin. MWDEU cites Jespersen as speculating that the preference for who over that was an attempt to conform to the Latin pronouns, that having no Latin correlative. But summing up usage over the centuries, MWDEU says, "That is definitely standard when used of persons."
Bryan Garner gives the imagined distinction the back of his hand. Garner's Modern American Usage says flatly, "Is it permissible to say people that, or must one say people who? The answer is that people that has always been good English, and it's a silly fetish to insist that who is the only relative pronoun that can refer to humans."
In Miss Thistlebottom's Hobgoblins, Theodore Bernstein writes, "Since when is that rather than who permissible in referring to persons? That answer, of course, is: since the language was in its infancy." He goes on to cite Fowler, who made the distinction that who suits particular persons and that generic persons." (Pray note that I am not bringing in some bolshie fais ce que voudras** linguist, but rather a determined prescriptivist editor who was exposing this sham distinction to daylight more than forty years ago.)
I have made the same distinction between particular and generic references in previous posts, citing "The people that walked in darkness have seen a great light" (Isaiah 9:2) and "The Girl That I Marry" (Annie Get Your Gun, 1946). I had hoped that adherents of the bogus rule would quail at the prospect of coming up against Lancelot Andrewes and the other forty-six translators of the Authorized Version, not to speak of Irving Berlin. But they persist stubbornly in their error and will not be enlightened.
Not that they are likely to heed the AP Stylebook, either. But it would be a good and noble thing to add one sentence to the who, whom entry, immediately after the first:
That may be used to refer to an unknown person, a group of people, or a nation.
I commend it to your good masters' attention.
*That split verb didn't bother you all that much, did it?
**Rabelais, "Do what you will."