I don't even understand this at all. If you believe gender equality is an intrinsic good then any women's gain up to gender equality would be a gain for anyone who has that principle regardless of their gender.
Do you think that black emancipation from slavery was "white's loss". It's just such a nonsensical position to hold.
The race comparison doesn't hold in quite the same way, because there isn't automatically a heredity line. One group can just exploit the other indefinitely.
First, I believe that women have privileged position compared to men. So tipping the scales in favor of women removes gender equality.
Second, comparison with black emancipation makes no sense. For evolutionarily foreseeable future, as long as humanity exists, so will men and women, and they need to get along with each other. Meanwhile you could imagine a perfectly functional world without emancipated black slaves.