With about 1.4 million associates, Walmart is the nation’s largest private-sector employer. The wages it pays set the benchmark for the rest of the retail sector. In most states, associates earn an average of $12 or $13. (In Alabama, for example, associates earn an average of $12.53). Annualized, that comes out to about $25,000, which is barely above the poverty level for a family of four (PDF). Walmart critics dispute these numbers. A report by IBISWorld—an independent market-research group—states that the average Walmart’s associate makes $8.81 per hour. That translates to only $15,576 a year for full-time workers.

So it’s not surprising that Walmart has become a target for critics of low wages. In July, for example, the Washington, D.C., City Council passed a measure that seemed aimed at keeping Walmart out—unless it agreed to raise wages sharply.

One of the most adamant grillers of Walmart recently has been The Nation, the venerable left-leaning political and cultural magazine. The Nation recently posted an open letter to company CEO Mike Duke and the Walmart board of directors demanding that Walmart start paying its workers a minimum wage $12 an hour. The letter also includes an online petition that readers can sign.

Walmart is clearly growing tired of being a punching bag and poster child for low wages. So on Wednesday morning, Steven Restivo, a senior director of communications at Walmart, sent out a snarky email directed at The Nation under the subject line: “people who live in glass houses…”

The Nation—“America’s leading progressive print and online magazine”—recently encouraged its readers to sign an open letter demanding that Walmart increase wages to $12/hour and this article called our company one of the “biggest abusers of low-wage labor.” In an ironic twist, ProPublica recently reported that starting this fall, “interns at the Nation Institute will be paid minimum wage for the first time in the history of the 30-year-old program.” As ProPublica noted, The Nation has been paying its full-time interns a weekly stipend of $150 per week—less than the current federal minimum wage rate of $7.25 per hour.

Ouch.

Indeed, the retail giant has a point. Internships at magazines of ideas are notoriously low-paying. The Nation interns, who are paid $150 a week, by the Nation Institute—a small nonprofit that raises money to support serious journalism—recently wrote a letter to the publication asking “The Nation and The Nation Institute to take the lead” in redefining the standards for the industry and pay their interns what they believe they deserve. The Nation announced via twitter on August 1 that this fall, for the first time in the history of the 30-year old program that it will pay interns the minimum wage: $7.25 an hour. The intern program also provides housing, monthly metro cards, and scholarships to the interns. Interns are also paid for any writing they do for The Nation’s magazine or website.

Even with the raises, The Nation interns still won’t be rolling in it by any standard, and they’ll still be making significantly less than Walmart associates. In addition, Walmart employees get access to health benefits. A few things worth keeping in mind.

Most obviously, there is a difference between full-time Walmart employees, who are trying to support a family on their wages, and The Nation’s interns, who are there mostly for experience and exposure. According to the Nation Institute: “The difference here is that what The Nation has challenged Walmart on is low wages for people in perpetuity as their full-time employment. These are wages that are meant to support families working at Walmart with no end in sight. Our internship is an educational, time-limited engagement that provides a unique training experience for participants. They are wholly different issues.”

What’s more, in discussing the impact of the wage boost, The Nation seemed to validate one of Walmart’s basic points about its wages. Many companies say sharply boosting the wages of entry-level employees would likely lead to less hiring. Companies and organizations have only so much they can spend on wages, after all. Push too hard on boosting the minimum wage, and you’ll wind up with fewer positions. In a statement to ProPublica, the Nation Institute director Taya Kitman said: “We are not yet certain how this will work out long term, but for the fall we are anticipating hiring ten interns rather than twelve.” The Nation Institute plans to continue fundraising in order to be able to further increase intern wages in the future.

Walmart’s missive ended with a quote it cribbed from the New York Post: “Every so often, some enterprising soul points to the gap between what our esteemed champions of social justice preach for others and what they practice themselves.”

Touché!