We all have our tiny little passions. We all get frustrated when others violate those passions -- especially when there seems to be no penalty. (How much delight am I taking in the fact that the ball-hog Kobe Bryant will likely miss the playoffs this year?)
But as friendly as you try to couch it, when you "protect apostrophes," you come off as a nag. You're trying to enforce your vision on others. And if you yourself aren't perfect in that vision, you open yourself up to charges of hypocrisy. Wouldn't it be better to have an Apostrophe Appreciation Society that went around looking lovingly at grammatically correct billboards? (Not as much fun to participate in, but healthier for society as a whole.)
Seems to me just one more case of moral absolutism gone overboard. There are instances -- murder being the easiest example -- where it's good for society to not only identify but enforce moral absolutes. There are also instances -- the newsiest examples being grammatical correctness and the Schiavo debacle -- where our desperate hunger for an easily-identifiable absolute tends to create them where they're too complicated to enforce.
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