It wasn't just libertarians, Rand tended to dislike everyone. She would excommunicate any of her friends and associates for the smallest deviation from her own beliefs
This right here. It's not so much a logically consistent disagreement with 'libertarians' so much as her own brutal personality problems and extreme ego (which Rand worship didn't really help from her 'inner circle', etc).
Enjoy...
http://www.aynrand.org/site/PageServer?pagename=education_campus_libertarians
Q: Do you think Libertarians communicate the ideas of freedom and capitalism effectively? [Q&A following LP’s “Objective Communication,” Lecture 1, 1980]
AR: I don’t think plagiarists are effective. I’ve read nothing by a Libertarian (when I read them, in the early years) that wasn’t my ideas badly mishandled—i.e., had the teeth pulled out of them—with no credit given. I didn’t know whether I should be glad that no credit was given, or disgusted. I felt both. They are perhaps the worst political group today, because they can do the most harm to capitalism, by making it disreputable.
Q: Why don’t you approve of the Libertarians, thousands of whom are loyal readers of your works? [FHF: “The Age of Mediocrity,” 1981]
AR: Because Libertarians are a monstrous, disgusting bunch of people: they plagiarize my ideas when that fits their purpose, and they denounce me in a more vicious manner than any communist publication, when that fits their purpose. They are lower than any pragmatists, and what they hold against Objectivism is morality. They’d like to have an amoral political program.
Q: The Libertarians are providing intermediate steps toward your goals. Why don’t you support them? [Ibid., 1981]
AR: Please don’t tell me they’re pursuing my goals. I have not asked for, nor do I accept, the help of intellectual cranks. I want philosophically educated people: those who understand ideas, care about ideas, and spread the right ideas. That’s how my philosophy will spread, just as philosophy has throughout all history: by means of people who understand and teach it to others. Further, it should be clear that I do not endorse the filthy slogan, “The end justifies the means.” That was originated by the Jesuits, and accepted enthusiastically by Communists and Nazis. The end does not justify the means; you cannot achieve anything good by evil means. Finally, the Libertarians aren’t worthy of being the means to any end, let alone the end of spreading Objectivism.