Radley Balko marvels at the fact that Barney Frank can be both a fan of John Stuart Mill and "a big government socialist on most economic issues". The implication - or assumption - is supposed to be that Frank is being inconsistent, presumably because he hasn't thought through his beliefs very carefully.
Except that, as it turns out, John Stuart Mill's Utilitarianism is one of the most influential books in the history of...egalitarian liberalism! Mill was a big fan of freedom, definitely. At the same time, though, he thought that the organizing principle of society - and life generally - should be the "greatest happiness principle", which "holds that actions are right in proportion as they tend to promote happiness, wrong as they tend to produce the reverse of happiness." That is the fundamental ethical principle of Mill's philosophy. Note that it says not a single word about liberty.
Once you factor in the law of diminishing marginal utility, Mill's ethics offer a powerful argument that will frequently justify redistributing significant quantities of wealth from the rich to the poor - i.e., big government socialism, as defined by our right-wing friends at Reason.
And not to hassle Balko with needless details, but Mill was also an advocate, in many cases, of government intervention, provided that it was to the benefit of society's aggregate happiness. In later years he was essentially a socialist himself, but even earlier on he advocated free markets primarily because he thought they were an effective way of promoting happiness, not because they were ends in themselves. And that really gets at the central flaw of libertarian thinking, doesn't it?