You probably saw this T-Mobile ad if you watched the Super Bowl on Sunday. It featured a bunch of cute babies and a narrator offering a series of statements about their futures, including this one: “You’ll demand fair and equal pay…You will be heard, not dismissed.”

Today, Christina Hoff Sommers takes the ad to task in a piece written for The Hill. Of course, we’ve all been over the gender pay gap myth many times before, and that’s really Sommers’ point. This argument keeps returning because the people promoting it are really enthusiastic about it, regardless of the truth:

What explains the appeal and staying power of a groundless claim about systemic pay injustice? For one thing, there is a lot of statistical illiteracy among journalists, activists, political leaders. There is also an admirable human tendency to be protective of women: stories of female exploitation are readily believed, and skeptics — especially men — risk appearing indifferent to women’s plight. But these are not the root causes. The wage gap myth endures because it has the support of a passionate and effective lobby. An army of gender scholars and activists in our universities and women’s research institutes believes there is systemic gender discrimination in the labor market and they promote this myth in their classrooms, textbooks, and factsheets. They rarely engage directly with critics and skeptics outside of the gender equity universe, but they have forged an alternative route to success: Networking… The wage discrimination myth has made it to the Super Bowl because it has become an enthusiasm — with rallies, speak-outs, affinity networks, even its own holiday. The truth about pay disparities can hardly compete — it is addressed to reason rather than emotion and requires a few minutes of explanation. It does not lend itself to heartrending vignettes about innocent girls and babies facing a future of injustice. Most of all, the truth lacks a lobby. For the time being, expect more ads.

This isn’t the only progressive enthusiasm which has a “passionate and effective lobby.” Case in point, Black Lives Matter co-founder Patrisse Cullors is still referring to the death of Trayvon Martin as a “cold-blooded” murder. That’s actually the opposite of the truth as clarified years ago by witnesses and a jury. But it doesn’t seem to matter. Something similar could be said about the handling of Michael Brown’s death by BLM and the media. “Hands up, don’t shoot” was another enthusiasm not based in fact. There are quite a few of these on the left which, at times, seem immune to criticism.

As for the gender pay gap, it is largely the result of other factors, including women’s personal choices. From the Washington Post’s fact-checker:

Women also tend to leave the workforce for periods to raise children, seek jobs that may have more flexible hours but lower pay, and choose careers that tend to have lower pay. (BLS data show that women who have never married have virtually no wage gap; they earn nearly 94 cents for every dollar a man makes.)… In 2011, economists at the Federal Reserve Bank of St. Louis surveyed economic literature and concluded that “research suggests that the actual gender wage gap (when female workers are compared with male workers who have similar characteristics) is much lower than the raw wage gap.” They noted that women may prefer to accept jobs with lower wages but greater benefits (more flexible parental leave) so excluding such fringe benefits from the calculations will exaggerate the wage disparity. For instance, a 2013 article in the Daily Beast, citing a Georgetown University survey on the economic value of different college majors, showed that nine of the 10 most remunerative majors (such as petroleum and aerospace engineering) were dominated by men, while nine of the 10 least remunerative majors (such as social work and early childhood education) were dominated by women.

There is some portion of the raw wage gap which has not been explained and could be attributable to discrimination, but it’s a fraction of the gap as the claim is usually presented. All of this readily available information should prevent major corporations from creating expensive ads based on dubious claims. But as Sommers points out, the left-wing lobby is devoted to this claim. That’s enough to make sure it keeps coming around again.