It doesn’t surprise me that some 20-somethings and 30-somethings are drawn to socialism. They’ve grown up with the left-of-center rhetoric about “fairness” and persistent take-downs of the wealthy. But columnist Steve Chapman writes that free marketers have themselves to blame for the embrace of socialism.

The demise of Marxism in so many countries has actually been a boon to the left. Socialism was once seen as the path to communism. But with the Soviet Union dead and China only pretending to be socialist, those fears have faded.

It doesn’t help the reputation of capitalism that many of those fervently opposed to government interference and redistribution are strongly at odds with millennials on social issues—including gay rights, racial inequality, immigration, gun control, and abortion rights.

The refusal of most conservatives to recognize the human role in global warming alienates those who will have to live with the environmental damage their elders did. In many minds, free markets have been discredited by their association with intolerance, rejection of science, and disregard for the poor.

Mr. Chapman has it wrong. It is leftist rhetoric — not reality — that connects free markets with the ills he describes. Markets are about unleashing potential and opportunity. Mandates crush opportunity. Markets open doors. Mandates close doors.