Because power isn't clear cut or stratified along gender lines. Want to see what clearly stratified power looks like? Compare white and black populations in the US. You have less access to education, greater rates of imprisonment, greater rates of homelessness and poverty. Across the board. Not one stat has white people coming out worse off than black people in the United States.
Yet when it comes to men and women, the discrimination is all over the place. Women make less money but they're overrepresented in college. Positions of power are more likely to be occupied by men, but so are prison cells or the graves of dead workers.
I will happily once again repeat the issue that you've yet to address. No other intersectional axis is in this situation. Every other example where we know power is stratified does not look like this. Instead we have to jump through hoops to maintain a narrative. That's not a clear stratification of power between genders. Men are more empowered in some ways, women more empowered in others. Again, this is the only intersectional axis along which anything remotely like this happens.
One more time, explicitly. I deny power stratification between genders because nowhere else where we see clearly stratified power do we see discrimination against parties on both sides of it. Nowhere. Not once.