The apologetic bee in your bonnet is based on a refusal to admit that words change meaning through time.  The linguistic argument about the word "exhorter" could not have been made even a hundred years ago because too many people then would have understood its context. 
Suppose I should jump on the phrase "author and proprietor," which Joseph Smith used to get his copyright, and insist that only the first definition of the word "author" in a modern dictionary ("original writer of a literary work") could be cited in any article about the BoM, declaring that any other definition would mislead the reader. Q.E.D., Smith was a fraud by his own admission.
I appreciate the cleverness of some Mormon apologetics, but this argument about the word "exhorter" is (please, pardon my bluntness) ignorant.