(1) With adverbs, the writer usually tells us he or she is afraid he/she isn’t expressing himself/herself clearly, that he or she is not getting the point or the picture across.This is almost painfully clumsy to read. Of course, it is a reaction to the years of prescriptive "grammarians" telling us, untruthfully, that he is a generic pronoun referring to anybody, which in those bad old days would have made King's sentence look like this:
(2) With adverbs, the writer usually tells us he is afraid he isn’t expressing himself clearly, that he is not getting the point or the picture across.
The problem with this last sentence is that while the Noun Phrase the writer carries no gender, he does: it's masculine. We know that he has never been a true generic, and we also know that the idea that it should be used as generic originated in England as Rule 21 in John Kirkby's 1746 treatise Eighty-eight Grammatical Rules. Rule 21 states that male is "more comprehensive" than female and therefore he should be taken to include both feminine and masculine gender.
It was reaction to this rule that got us he/she-ing and himself/herself-ing all over the place. The result is clumsy language; if you don't believe me read sentence (1) again. Fortunately, there is a more elegant way: Make the sentence plural. In English, the third-plural pronouns carry no gender at all, and King's unhappy screed against adverbs would look like (3):
(3) With adverbs, writers usually tell us they are afraid they aren’t expressing themselves clearly, that they are not getting the point or the picture across.
Why don't we just do this all the time? I think there's another aspect of our culture at work against us, and that is the tyrrany of the number one, or singularity. One is one of our magical numbers: we like one Right Answer, one Most Valuable Player, one Winner, and so on. We prefer singular when we can get it, and our default form for talking about generic entities is singular (the writer, the whatever).
By the way, King also recommends that writers have at hand a copy of Strunk and White's Elements of Style. This is bad advice, unless accompanied by the caution not to take anything they say about grammar too seriously. But do start putting sentences in plural form, to avoid both Kirkby's wrongheaded gender prescriptivism as well as the awkwardness of those double pronouns.