Before Warby Parker came around, you had to build your own glasses until your hands bled—remember that? Now, buying corrective lenses is fun and (relatively) cheap, and Warby sells the startup chic de rigueur. So chic, it appears, they can get away with paying crappy salaries.

Warby Parker isn't just a corporation that sells goods and services in exchange for money—it's a "B Corporation," a sort of shambling creature, halfway between the dictates of the free market and the whims of philanthropy. "B" firms like Warby Parker agree to place some sort of emphasis on social good in addition to the ol' profit motive, and are technically beholden to this in addition to their shareholders. The New Yorker charitably details the arrangement in a writeup this week:

Why would any company tie its hands this way? Neil Blumenthal, one of Warby's co-founders, told me, "We wanted to build a business that could make profits. But we also wanted to build a business that did good in the world."

This is why Warby Parker donates a pair of eyeglasses to someone who can't afford them for every pair of eyeglasses a Westerner with money buys. That's great, and commendable on its own, but allows for some profound HR advantages:

Dave Gilboa, another Warby co-founder, told me that, at the operational level, having a social mission can offer distinct advantages. It's an important way for a company to attract and retain talented employees. Survey data show that workers—especially young ones—want to work for socially conscious companies, and will take less compensation in exchange for a greater sense of purpose.

Here are a lot of words that mean one thing: like Vice, Warby Parker, which paid a model to pretend to stand and read during a Soho launch party, thinks it can pay its employees less because of its image. One Valleywag reader provided me with a copy of his signing contract, showing he will make only $12 an hour for full-time sales work:

Granted, it's a temporary position of six months, but one with all the obligations of a full-time staff spot. "Associates aren't eligible for benefits," my source complained, "but still have withholdings taken from their $12/hr paychecks." Even well above the New York State minimum wage, $12 per hour is a difficult amount of money to get by on within range of Warby's West Village HQ.

A look at employee reviews of the company on Glassdoor, a site that aggregates feedback and salary information, shows widespread complaints of stinginess:

Although the job is fabulous, the pay is lacking a bit, especially compared to other startups of similar size in NYC.

If you're not at a high level title, there is very little compensation for experience regardless of tenure..You can't have the senior positioned individuals be the only employees who can afford to live comfortably. The average low end rent in NYC is 30K/yr. You're asking people to spend more than half their income on rent.

Salary growth doesn't exactly match what the company seems to be making, and that is frustrating.

The pay is on the lower side...

Advice to Senior Management – Increase salary.

And so on. It's simple to see why young professionals would flock to "B" startups like Warby Parker, where they can reap the benefits of a "hot company" and still feel good about themselves after work. But the difference between Warby Parker, which tries to do good while chasing profits, and a non-profit, is ample. The former is not a philanthropic endeavor, no matter how you slice it—and any company valued at half a billion dollars shouldn't use helping strangers as an excuse to not do right by its own people.

To contact the author of this post, write to biddle@gawker.com