Within libertarian circles, I've seen folks differentiate between "capital L" libertarians who think liberty is an end in itself and "lower case l" libertarians who are libertarian on utilitarian grounds.
The study says that libertarians are "libertarians were moderately more utilitarian than conservatives, and slightly more utilitarian than liberals." But they also value liberty as a terminal value more than liberals or conservatives. I don't see how this can be reconciled.
It can be reconciled if there are several other values aside from liberty that liberals and/or conservatives value and libertarians don't. (As the article suggests.)
Defendind libertarianism in a conceptual ground don't make much sense if don't supported with free market policies. "As a end in itself" is a heuristic to average in situations where you don't have direct acess to data.
An article from the Wall Street Journal. The original title might be slightly mind-killing for some people, but I found it moderately interesting especially considering that many LessWrongers formed part of the data set for the study the article talks about and a large fraction of us identified as libertarian on the last survey.
Inside the Cold, Calculating Libertarian Mind
The original paper.
Understanding Libertarian Morality: The Psychological Roots of an Individualist Ideology