There may be some dumb people out there misinterpreting the stat, but there are also an incredible number of people "straw-manning" the ENTIRE opposition as glib.
For example, I've seen people cite the White House page as "fallen to the delusion", when in fact it is quite explicit:
https://www.whitehouse.gov/issues/equal-pay
> In 2014, the typical woman working full-time all year in the United States earned only 79 percent of what the typical man earned working full-time all year. Phrased differently, she earned 79 cents for every dollar that he earned. The pay gap is even greater for African-American and Latina women, with African-American women earning 64 cents and Latina women earning 56 cents for every dollar earned by a white non-Hispanic man. Decades of research shows that no matter how you evaluate the data, there remains a pay gap — even after factoring in the kind of work people do, or qualifications such as education and experience — and there is good evidence that discrimination contributes to the persistent pay disparity between men and women. In other words, pay discrimination is a real and persistent problem that continues to shortchange American women and their families.
There is absolutely no lie or imprecision there. It is a common rhetorical trick to tar your entire opposition as idiots. The people claiming that the pay gap is a "myth" are just as just as zealot-like as the people misinterpreting the 77c figure.