Surprise! I am not going to criticize libertarianism here, and I expect that most libertarians will agree with me on this point. Certainly, people like Rand and Rothbard would.
But there is a certain subspecies of libertarian who makes the following sort of argument:
"We know that morality is all just subjective preferences. So no one has any right to interfere with these subjective choices of others, so long as they concern consenting adults."
But if the first sentence is true, then the second sentence appears to be nonsense, as it seems to assert that it would be objectively wrong for someone to interfere with these choices. But that, of course, contradicts the assertion of the first sentence.
In short, if the Taliban enjoy stoning an adultress now and then, where does this sort of libertarian get off griping about their subjective preferences? After all, it is just his subjective preference that they stop.
By the way, it is not just this type of libertarian who has this problem: John Rawls' theory of justice runs aground on similar shoals.