Greed: Libertarianism is based on the "I got mine" idea. It reeks of social darwinism and completely ignores the idea that all people don't start out equal. If "work" translated into "wealth" as libertarians belive, we'd have a lot of rich immigrants who work 2 or 3 jobs. But instead, we have a lot of people born into money and positions of privilege. And you've gotta have money to make money, which further reinforces that social hierarchy. The rich just get richer.
Slacktivism: Libertarian philosophy is based on the idea that our problems will simply be solved if we don't do anything about them. The "invisible hand of the free market" will take care of everything. People don't want to go through the effort of actually solving problems any more, and just expect someone or something else to take care of it.
Inequality: not just money (addressed in point 1) but in race, class, gender, etc. Libertarians don't recognize that we're not all born on an equal footing. Society has inherent biases and inequities that the free market just won't solve.
Irrationality: Libertarians just don't recognize the reality of the human situation. They say that if a corporation is behaving unethically, then people will stop buying from them, right? This is true if the people know about that behavior. And if the corporation voluntarily gives out that information, because most corporate disclosures are due to government requirements. And that the people in general are actually buying their product, instead of a distinct sect of the population (for example, most people don't have the means to boycott Rolls Royce in the first place). And it is an immediately recognized harm instead of something that presents itself years later after the harm is already done (example, lead paint). And the people actually care enough about that wrong to justify spending more on a different or inferior product. And they are able to overcome transaction costs of organizing a large campaign against this wrong. And it will make such an impact on the company's revenues that it will cause them to change that behavior. And if their competitors are not engaging in the same practice.
Uncompromising: Ron Paul is the perfect example of this. They view the world in absolutes and are unwilling to recognize shades of grey. Campaign finance, for example. Citizens United has shown how corrupt and controlled the campaign finance system is, but Libertarians maintain that we need less restrictions on who can donate to campaigns because it's a restriction on speech. Billionaires like the Kochs and Sheldon Adelson could simply buy the candidate they want outright, without going through the disclosure requirements of PACs. They don't recognize that "free speech" is not sacrosanct and there are perfectly valid reasons where something that is barely speech (money) should be restricted for perfectly valid purposes (preventing corruption)
Edit: I didn't think I would need to make this clear, but this is my opinion.
