Yeah I (wrongly) figured that HR would do scans of salaries based on gender, race, disability etc to make sure there were no statistically significant differences that could lead to ammo in a lawsuit situation.
BTW all of what you described is not unique to women. I have at least few friends that don't negotiate, don't seek alternative offers and because of that are disadvantaged when it comes to earnings. Periodic pay rise is just a device to dissuade employees from seeking their market value and appropriate compensation. The main reason for its existence is to profit from what happened to you.