They’ve transformed child abuse into a way of life:

http://www.fourhourworkweek.com/blog/2008/07/15/escaping-the-amish-part-1/

“Thick libertarianism” of the sort Micha advocates makes sense if your goal is to spread freedom to others while maintaining a “truce” of the sort Todd brought up. That said, I still think it’s important to maintain a thin concept of liberty, for the sake of promoting clear thinking and avoiding unnecessary confusion. Anyone who’s not convinced of that should read Daniel Klein’s essay “Mere Libertarianism,” which I think of as the ultimate reply to those libertarians who try to expand the concept of liberty to include everything they think is good and important.

I share your belief in the importance of letting local/tribal/traditional cultures be left alone to do their own thing, in the sense that they should not be physically forced to change by a benevolent imperialist power. I hold this belief for pragmatic truce reasons you mention.

I would even take the position further than you do: In many cases, it is not wise to physically interfere with other cultural practices even when those practices explicitly violate property rights, despite us being justified in doing so. (For an explanation of where I’m coming from, see Chandran Kukathas’ Two Constructions of Libertarianism, which touches on many of the same issues as Jacob Levy’s Liberalism’s Divide.)

But this doesn’t mean that libertarians as libertarians have to or should keep silent about cultural practices we deem morally praise- or blame-worthy. Thick libertarianism is that much more important when you adopt a “Federation of Liberty” over a “Union of Liberty” approach, to use Kukathas’ language, or when you adopt a pluralist over a rationalist approach, to use Levy’s. The only way to convince other cultures that liberty is worth preserving is by engaging them in that argument, and rooting out those aspects of their culture that are inimical to freedom. Removing benevolent imperialism from the libertarian tool-kit makes the tool of peaceful but critical persuasion all the more necessary.

If the Saudis want to keep their women dressed in beekeeper costumes, I don’t think it would be wise for libertarians to physically interfere with them, but we might want to persuade them that this is a bad idea, if for no other reason than dissenting women are likely to be physically attacked if they don’t comply.

Children indoctrinated in intensely religious environments may never fully develop their capacity for autonomous consent precisely because of their lack of exposure to other options. Libertarians, as pluralists, have an interest in exposing these other options and persuading the sheltered that theirs is not the only way to live, if for no other reason than to better maintain the pluralistic pragmatic truce.