Queue up the "Somalia" thread here
Rather than being bitter that people keep bringing up the flaws of your favorite ideology, why don't you think up ways to fix those flaws? We all got a rather thorough lesson about what happens when ideological purity trumps reality with Soviet Union, and are currently getting a repeat lesson with neoconservatives. Surely you don't want your ideology moving from "questionable" to "inherently evil" category in the annals of history?
Then again, an untested ideology is perfect. It could solve all the world's problems if only people adopted it. Just like a lot of people dream of a perfect book (or game, or movie, or whatever) they'll write one day, but never will, because then it would be subject to actual criticism. So I wonder if libertarians actually want people to vote libertarian, at which point they could no longer dismiss criticism with comments like yours without it backfiring horribly, or if they'd rather just stay in the margins where they can build their utopia in the safety of castles in the sky?