@spendius,
S: I don't think a prescriptivist would choose that comparison.
You're unaware of the idiocies they do choose because you are unaware of the workings of language.
S: Comparing prescriptivism to disease is a bit circular. You win your bottom-line argument with a verbal flick-of-the-wrist and have to be assuming that your audience is dim.
Those that advance these silly notions about language are dim, exceedingly so. Joe is a dandy example. Try it, Spendi, try to defend one of your favorite rules.
You saw Joe, eyes all buggy, flailing away, saying nothing but desperately pretending he was saying something.