JASON RILEY: Why Liberals Oppose Ben Carson: Trump’s HUD nominee grew up poor, and he knows public housing isn’t where people prefer to live.

Do yourself a favor and hold off on joining the liberal outrage over Donald Trump’s cabinet choices—or at least better understand what’s happening.

Critics say the president-elect is tapping individuals who lack experience or who want to eliminate the very agencies they will be tasked with running. But the real concern on the political left is that the incoming administration will be all too competent at shifting the priorities of some federal agencies while reining in others.

The main objection to school reformer Betsy DeVos, Mr. Trump’s pick for education secretary, is not that she’s never been a classroom teacher but rather that she wants to expand school choice, which threatens union control of public education. Green groups don’t want former Texas Gov. Rick Perry to become energy secretary because he opposes federal subsidies that facilitated boondoggles like Solyndra. And they don’t want Oklahoma Attorney General Scott Pruitt anywhere near the Environmental Protection Agency due to his history of fighting efforts to impose through executive fiat environmental regulations that Congress has rejected.

One of the best examples of liberals using personal attacks as a pretext for policy disagreements is the campaign against retired neurosurgeon Ben Carson, who has been selected to head the Housing and Urban Development Department. The New York Times depicts Dr. Carson as an antigovernment ideologue with a “warped view of housing.” The Daily Beast chides him for criticizing government efforts to help low-income minorities by sprinkling them throughout wealthy suburbs where they couldn’t afford to live without government subsidies.

Dr. Carson grew up poor in Detroit and Boston, an experience that he chronicles vividly in his memoir, “Gifted Hands.” His upbringing doesn’t make him a housing expert, but like the general who knows war and is therefore less likely to venture recklessly into a new one, Dr. Carson’s background does make him better able to empathize with the plight of the poor.

Besides, if the state of inner-cities is any indication, the last thing low-income residents need is more of the same so-called expertise that Dr. Carson lacks. New York City is home to the nation’s largest public housing program, writes Howard Husock of the Manhattan Institute, “and the average resident has spent 22 years living in a subsidized home.” Are HUD’s policies helping these people or trapping them?

HUD is an outgrowth of Lyndon Johnson’s Great Society, and its original goal was to address the housing needs of America’s poor. Today, it serves as a blunt tool for social engineers who are hellbent on achieving “racial balance” in residential housing patterns—whether the intended beneficiaries want it or don’t.

HUD’s original goal was to establish voter farms for the Democrats, and it’s been wildly successful in that. Everything else is just noise. What worries Democrats about Ben Carson is that he might upset that applecart.