It is true that conspicuous displays of wealth are vulgar and irritating. But they are not something that a nonenvious principle of public policy needs to acknowledge.

Poverty is never good. Difference, including economic difference, often is. It is why New Yorkers exchange goods with Californians and with people in Shanghai, and why the political railing against foreign trade is childish. It is why we converse, and why today is the great age of the novel and the memoir. It is why we celebrate diversity — or should.

A practical objection to focusing on economic equality is that we cannot actually achieve it, not in a big society, not in a just and sensible way. Dividing up a pizza among friends can be done equitably, to be sure. But equality beyond the basics in consumption and in political rights isn’t possible in a specialized and dynamic economy. Cutting down the tall poppies uses violence for the cut. And you need to know exactly which poppies to cut. Trusting a government of self-interested people to know how to redistribute ethically is naïve.

Another problem is that the cutting reduces the size of the crop. We need to allow for rewards that tell the economy to increase the activity earning them. If a brain surgeon and a taxi driver earn the same amount, we won’t have enough brain surgeons. Why bother? An all-wise central plan could force the right people into the right jobs. But such a solution, like much of the case for a compelled equality, is violent and magical. The magic has been tried, in Stalin’s Russia and Mao’s China. So has the violence.

Many of us share socialism in sentiment, if only because we grew up in loving families with Mom as the central planner. Sharing works just fine in a loving household. But it is not how grown-ups get stuff in a liberal society. Free adults get what they need by working to make goods and services for other people, and then exchanging them voluntarily. They don’t get them by slicing up manna from Mother Nature in a zero-sum world.

We could use state violence to take wealth from billionaires like Bill Gates and give it to the homeless, achieving more equality. (Mr. Gates is in fact giving away his fortune, to his credit.) Short of expropriation, we can and should join in supporting a safety net, keeping the violence to a minimum. K-12 public education, for example, should be paid for by compelled taxes on all of us. But we should not be doing a lot more.