Yesterday’s Language Log provides a useful analytical light on a pervasive conceptual confusion. Evidently John Prescott says that he has problems with English grammar, when LL’s more careful examination of his remarks shows that he devises grammatically-correct statements that make no sense. Admitting that you don’t understand grammar makes you a regular bloke, though; stuck-up prescriptivists have given clear expression a bad name. Admitting that you can’t think straight or utter a coherent though, however, tends to give even casual voters reason to hesitate before reelecting you.
I suspect that a similar dynamic affects preaching; in homiletics as well as in politics, it’s quite possible to make oneself popular (perhaps even attract a positive reputation) while speaking utter gibberish.