"Now, I've got nothing against libertarians in general -- but some of them seem incapable of listening to other folks' viewpoints without filtering them through a kind of ideological anti- virus scanner so they can reject anything that doesn't fit inside their world view."

I've often felt that way about many libertarians. Also socialists. Also monarchists, republicans, democrats, anarchists, Tories, liberals, communists. Etc. In short, much as I agree with you, I think that when you wrote "libertarians," you misspelled "people."