Sane here, mate, but I fear you are fighting a losing battle - the false apostrophists will take no notice of your admirable homily and continue to mangle our language and its usages.
Even explaining about possesseion is lost on many - it is fraught with traps for the unwary. Someone on another thread recently talked about the "player's lounge" (sic) when alluding to the lounge used by all the players - I almost replied and asked him which individual player had a lounge of his own.
Still, perhaps not as bad as the shop I saw with a display of apples called "Golden Deliciou's". I felt like going in and buying one golden deliciou. But I feared the irony would be lost on whoever served me.