It is having government treat some potential labor as different than other potential labor sources. You wouldn't think for a second that imposing a tariff on a good is an anti-capitalist maneuver. But the second that tariff is placed on a provider of labor, you suddenly can't see how that is also anti-capitalist. From the Libertarian think tank The Future of Freedom Foundation: http://fff.org/explore-freedom/article/immigration-socialism-freedom-free-market/ I can't even imagine what your reaction would be to state planning in other areas. But in the labor market, as it is part of conservative orthodoxy, you turn a very big blind eye to the existence of state control that you supposedly don't like. And thus why the giant blind spot exists. Because free markets in this case might help Democrats. And you can't have that.