In the U.S., most people don't identify themselves as poor. But that doesn't mean they're well off.

U.S. household debt rose to a level not seen in five years in the third quarter of 2013, according to the latest data from the Federal Reserve Bank of New York. In a recent Wall Street Journal/NBC News poll, 26 percent of respondents expressed worry over being able to pay for groceries and utilities. Meanwhile, wages were flat or declined for the entire bottom 60 percent of workers from 2000 to 2012, despite productivity gains over the period, according to the Economic Policy Institute's latest "The State of Working America."

Given such stark figures, it's little wonder why the war on "inequality" has become so ubiquitous. Not only did President Obama recently call it "the defining issue of our time," New York City Mayor Bill de Blasio sailed into office after making it a focal point of his election campaign--calling New York a "tale of two cities," as he described a Dickensian gap between rich and poor.

Even the Pope recently railed against policies of exclusion and greed.

As entrepreneurs and business owners, the questions of whether inequality is a problem and the steps the U.S. should take to stamp it out are obviously murkier. After all, many of those "wealthy" people, who politicians would levy new taxes on, identify as founders and business owners. And talking about how to put people on more equal economic footing can be challenging to reconcile with capitalist principles of private ownership and free markets.

But to focus just on one's own tax bill, though understandable, might just be doing your business a disservice. The health of the overall economy--rather than just your bank account--should be paramount for any business that relies on a vibrant base of customers. Bottom line: when people have less, they spend less.

So even the most business-oriented among us ought to consider taking up the flag against inequality. With a more equal population, average people will prosper and so will the majority of businesses. To hit this point home further and to commemorate the nation's annual celebration of Dr. Martin Luther King, who spoke fervently against racial and economic inequality, here's a sampling of his thoughts on the subject:

"Equality means dignity. And dignity demands a job and a paycheck that lasts through the week."

"Of all the forms of inequality, injustice in health care is the most shocking and inhumane."

"You can't win against a political structure where you don't have the votes. But you can win against an economic power structure when you have the...power to make the difference between a merchant's profit and loss."

"You know my friends, there comes a time when people get tired of being trampled by the iron feet of oppression… There comes a time when people get tired of being pushed out of the glittering sunlight of life's July and left standing amid the piercing chill of an alpine November. There comes a time."

"We, the disinherited of this land, we who have been oppressed so long, are tired of going through the long night of captivity. And now we are reaching out for the daybreak of freedom and justice and equality."

"I understand that you have an economic system in America known as Capitalism. Through this economic system you have been able to do wonders. You have become the richest nation in the world, and you have built up the greatest system of production that history has ever known. All of this is marvelous, but Americans, there is the danger that you will misuse your Capitalism."

"The misuse of Capitalism can also lead to tragic exploitation. This has so often happened in your nation."

"They tell me that one tenth of one percent of the population controls more than forty percent of the wealth. Oh America, how often have you taken necessities from the masses to give luxuries to the classes."

You may disagree with how to alleviate inequality, but as responsible business owners you can't ignore it. If Dr. King were alive today, he'd probably say as much--in his uniquely eloquent style.