I can't speak for everyone, but the ones to whom I'm referring (who comprise a fairly large chunk of libertarians are the ones who do some or all of the following:
1. Complain that every policy violates an originalist interpretation of the Constitution, without bothering to explain why such an interpretation is the best. (That's one of those articles of faith.)
2. Shriek about the immorality of taxation for the purposes of government spending, without bothering to explain why such a view is less moral than their own. (That's another article of faith.)
3. Respond to every government-related solution to any problem by saying that government can't do anything right and/or that the free market is always inefficient, with no evidence to support these hypotheses, and in some cases with evidence to the contrary. (That's another article of faith.)
4. The belief that every problem facing society is best solved by applying a few cliches from Atlas Shrugged.
These are the people to whom I'm referring. If you don't fall into any of these categories, then I'm not referring to you. But most libertarians do. Maybe there are a few libertarians who have decided that they are opposed to universal health care, social security, income taxes, the Federal Reserve, an interventionist foreign policy, drug laws, gun control, corporate bailouts, and public education by honestly assessing the merits and drawbacks of each of those policies on a case-by-case basis. But they are in the very small minority. Most of them reflexively decided they were opposed to those policies because they don't like government, and then went looking for "evidence" to support their view. Really no different than religious fundamentalism.