It isn't ignorance, it is the fact that many so called Libertarians are really Tea Party conservatives, they reliably vote Republican, trot out all of the Republican ideals, yet somehow still claim to be Libertarians, even when they aren't.  They just aren't willing to admit that they really are Republicans, so there is quite a bit of blurring between the 2 groups.  The full on Libertarians, the ones who vote Libertarian, are very different than the ones who reliably vote Republican, yet claim to be Libertarian.