Dear Metameta ~
It is all so simple, once you apprehend it.
Descriptive dictionaries pander to the lowest common denominator. They are driven by misuse. They enshrine the loss of fine distinctions. They justify the spread of ignorance. They pollute the word pool. They are doubtless of the Devil.
Prescriptive writing about the language is an act of great bravery. It withstands the slings and arrows of accusations of elitism, intellectualism, snobbery and the like. It requires education before use. It denies that one person's preference is as good as that of any other and thereby upholds the Platonic ideal. It is a thing much pleasing to God Himself.
Proponents of the former are responsible for signs which read "All-Nite Diner" and "Quik Lube." Of the latter, for great literature. Of the former, for the spread of illiteracy like a fungus growing on the skin of civilisation. Of the latter, for the preservation of books and libraries.
Descriptivists think Bart Simpson is actually funny. Prescriptivists know that Jeeves and Wooster are funny. D's drink blended whiskey; P's only single malt. D's wear "this year's colours" while P's know that the Creator ordained charcoal, navy blue and Harris tweed for all time.
Anything else I can explain for you?
