From Bryan Caplan at the Library of Economics and Liberty:
The minimum wage is far from the most harmful regulation on the books. Why then do I make such a big deal about it? Because it is a symbol of larger evils.
From the standpoint of public policy, the minimum wage is a symbol of the view that "feel-good" policies are viable solutions to social ills: "Workers aren't paid enough? Pass a law so employers have to pay them more. Problem solved." From the standpoint of social science, the minimum wage is a symbol of the myopic view that you can become an expert on X by reading nothing but the leading research that explicitly addresses X: "Does the minimum wage reduce employment? Read the top papers on the minimum wage. Problem solved."