They get that “77 cents” by comparing what women make, versus what men make, ignoring that men and women tend to go after different jobs.
Women go for jobs that have flexibility, do not require mandatory overtime, and have pleasant working conditions.
Conversely, if a job involves splicing wires in an ice storm, hammering shingles on a hot roof in August, crawling through sewers, or the possibility of having a gun pointed at the employee, the job will mostly be filled by men, who will want higher pay in exchange for the working conditions.
The whiners ought to be forced to write that on a blackboard 100 times.
“ignoring that men and women tend to go after different jobs”
Also more women than men will choose to raise children rather than being in the workforce.
It also ignores that fewer women work than men, period. Many of us are housewives or the like. We do not add to that pool, then.
As well, women tend to remove themselves from the workday via mostly childbirth/leave, so they have less time on the rolls and also that is disruptive to the work flow. So they naturally have that hit against them.