I don't think anyone could ask for a better example of systemic entrenched sexist bias than this quote. "It's okay, don't worry about it; they just don't want to be promoted as much as us men."
This is not that much different from the old "women enjoy being in their husband's kitchen and tending to the house, so it's okay most women are there instead of working independently!" Evidence clearly exists that lot of women used to enjoy being in the kitchen, but that doesn't mean women are less suited to work outside the kitchen -- to make an extreme example.