That's a confused analogy, because that's still a matter of fact. Hazlitt may have a value system in which government doesn't seem to accomplish anything valuable, but perhaps government accomplishes something that I find valuable instead.
Libertarians don't seem to care much for economic equality (hell, neither do I) but it's not the place of economics to choose our value system. And, as a matter of economic fact, maybe some non-libertarian policies will enforce economic equality! (Though even this is arguable.) Or, maybe I care a LOT about enforcing some kind of baseline standard of living for everyone, inefficiencies be damned. Maybe government can help me do this. But most libertarians are uninterested in that goal, too.
Economists don't get to decide what kind of society we want to live in any more than the rest of us. Their job is to tell us whether it's possible, how to get there, and what the costs will be.
the people who espouse economic equality are unaware of the outcomes of their actions. the whole point of being an economist is to draw people's attention to the non-obvious impact of various decisions about resource allocation.
the average person: A causes B! we want more of B so let's increase A!
economist: A and B are both side effects of C, pumping resources into A will not produce the desired effect.
I agree that economists should avoid making value judgments as much as possible so that people will listen to them. Robin Hanson recently debated Brian Caplan on exactly this point and made a very convincing case that economists should focus on the efficiency of outcomes.
