Ironically, you identify the thing that creates unequal opportunity: the "culture" that "comes along with gender minority work environments." Men have the opportunity to go into programming and be in a culture that is not stacked against them. Women don't. That's not equality of opportunity.
Acknowledging that the existence of a gender disparity in and of itself creates a hostile culture for the minority gets you halfway to understanding why attempts at eliminating the disparity directly are justified. And such measures are inherently temporary: once you eliminate then disparity that creates the hostile culture, you eliminate the need to take any affirmative measures to keep the new ratio.
You also precisely identify why you can't fix past institutional discrimination simply by no longer doing it. The past discrimination creates a culture that's hostile to the minority gender. That culture is self-perpetuating without active intervention (the "policing" you complain of).