I've seen a lot of Freepers lend a hand to their less literate forum mates, and rarely have I ever seen any of them be "smug" about it.
It strikes me as odd that so many people mistake correction for insult. Most often, those who offer a correction, are doing so out of an impulse to help - not to shame.
It is social Piety. People that are on this or other forums are here to get an idea across, not impress others with flawless punctuation. It’s not your place to “be helpful and correct it”. Those that do it, come off as Grammatically Pius, whether it is your intent or not.