Never get your information about libertarians from liberals.
That sounds all aphoristical and all, but the reality is that there is no fixed definition of "libertarian," any more than there is a fixed definition of "conservative." (We once tried to come up with a definition for "conservative" that covered all the regulars on the NC Forum, but eventually we gave up and went back to arguing about sports and barbecue.)
Everyone who considers himself "libertarian" defines the philosophy as being comprised of his personal beliefs.