Some theses

1) Libertarianism (like the liberalism of which it is a subset) is, as such, best understood as a political doctrine, not a comprehensive account of the good life and a desirable social order. Indeed, libertarianism is perhaps even more necessarily a political doctrine than is the kind of liberalism defended by John Rawls in Political Liberalism. The idea of a comprehensive libertarianism is more or less incoherent, since we need to be able to do something with our freedom, and every action we take forgoes other actions, forecloses some future possibilities. Randian Objectivism, by contrast, is a comprehensive doctrine, telling its adherents what music to prefer, what substances to inhale, what to value and what to disvalue in living a good life.

2) Two (understandable and appropriate) tendencies push us away from treating libertarianism as a strictly political doctrine.
a) One is that, as Matt says below, we libertarians come to libertarianism for a reason. There is a moral sensibility about liberty, power, subordination, human flourishing, etc. at the core of the attraction the political doctrine holds for a particular person. There is an initial hunch about something being unjust that gets built around.
b) We recognize that the political doctrine can only gain traction in the world if its adherents attract new adherents or build coalitions with other people. That means that our more-or-less informed hunches about which other people could be so attracted or would be open to such coalitions play a role. And informed hunches about that kind of thing will vary based on external social and political conditions: what the state is doing and is likely to do, what movements in civil society exist or are likely to exist, who is feeling distrustful of state action and who is feeling confident in it.

3) 2a and 2b need not be at all related. A person could be attracted to libertarianism because of an utter horror about laws regulating sexuality, and still look around the world of the mid-to-late 1970s and say “these conservative Christians who are terrified of state regulation of their private schools and universities are probably my best bet for a coalition in support of freedom, so I should emphasize their issues.” A person could have a core hunch that’s about the capitalist hero and the entrepreneurial spirit, and say “the hippies of 1967 or the Occupiers of 2011 have an anti-authoritarian ethos that’s an especially promising basis for attracting them or building coalitions with them.”

4) But, predictably and understandably, that’s not how most people think most of the time. Instead they imagine other people following their own trajectories. And their initial sense of friends and enemies carries over. So if their initial core intuition was about sexual freedom, it’s going to be hard for them to see the conservative Christians as their best allies.

5) Murray Rothbard was, as far as I can tell (and I never met him), entirely committed to thinking in terms of 2b. He was famously promiscuous in searching for allies, and changed his mind many times, from right to left and back again, about who the best allies would be. Since he was also an especially doctrinaire thinker (not necessarily a disparagement, by the way), whatever he happened to believe at any given time about strategy, tactics, and allies became, as far as he was concerned, the correct thing to believe, and could be the basis for breaking with people who didn’t agree. That means that, even though he was in one sense a strictly political-not-comprehensive libertarian, he was willing to treat social and cultural and symbolic issues as being of tremendous importance, and to treat those who disagreed with him on those issues at that moment as anathema.

6) Paleolibertarianism was thus in a real sense thick doctrine. The presence of hippies, non-Christians, drug users, porn readers, gays and lesbians, and people who are unsympathetic to romantic nostalgia about the Confederacy within the libertarian movement was an embarrassment to those who were trying to build an anti-statist coalition with southern whites Christians who felt persecuted by the world.

7) “Thick” attitudes of whichever type (one’s own authentic attitudes, or strategic guesses about other people’s) can, maybe often do, feed back in to the political core of the doctrine and affect how people perceive core political questions. To my mind, the cultural attitude of the paleolibertarians has meant that they systematically fail to see the entanglement of white racism with public and private tyranny in the United States. They over-appreciate the anti-central-state rhetoric that has accompanied the cause of the Confederacy and Jim Crow for more than a century and a half, and under-appreciate the magnitude of the violations of freedom that slavery and Jim Crow involved. In turn, my own view that the 1964 Civil Rights Act– including the bans on discrimination by non-state actors– was absolutely necessary to break the power of the Jim Crow state (since the white racist power-holders had deliberately built up institutions that played fast and loose with the public-private distinction and were perfectly capable of relocating state power on the nominally non-state side of the line in order to protect racial supremacy) no doubt strikes the paleos as a compromise of libertarian principle influenced by cultural attitudes.

Eight) [if I use the numeral I get an emoticon]  (4) and (7) mean that the overlapping-consensus political-liberal view isn’t wholly stable by itself.  The political doctrine isn’t so detachable from the thick views that support it as to allow simple joint agreement.  We come to our sophisticated political views with some unshakeable priors about who are good guys and who aren’t.  People who ostensibly share a thin view, but who each hold it in what the other thinks is a morally distorted and misshapen way, can’t be expected to just ignore those differences.