Suddenly all the males were dominated globally. How does that even happen? Actually is it global or is it regional? If it's regional, what complications do they suddenly have with other countries? Are they capable of fighting other countries? Are there other countries that are severely sanctioning them for having slavery?
If it is global, how did they manage to wrangle 50% of the population to give up their arms, their freedom and their autonomy?
If it is due to drugs, how did that occur? The drugs utilized aren't pacifying drugs, they're stimulants. They look like you're feeding them speed or cocaine or something, not something that makes them calm or docile.
Well it's hypnotism. Then how come the world didn't magically turn into a hentai land and some depraved men used the hypnosis on women? Was there a civil war?
Oh well the women just used powerful tools and weapons. Tools and weapons are just that, they're not locked by whether you have a taco or a chunchunmaru.
Right now we're seeing the result of what? 150 years of conditioning?
Plus, if anything, going back to chapter 3 where it was the declaration of the female victory that ended male reproductive function. This neutering didn't seem to remove the natural testosterone that men create, since we clearly see the women going crazy over the heavily muscular guys. And if anything, the loss of reproductive capability would have actually potentially put women in greater risk and danger of being turned into breeding farm animals for the purpose of ensuring the continuation of the human race.
If it's political power, that's going to be near impossible to wrangle it out. If it's societal power, we are currently seeing it employed to it's maximum efficiency, actually the highest form of oppressive power usage from women unto men was back when we were at the apex of MeToo. Even if we look at the most radical of feminist movements such as the one in South Korea, it's mostly about non-engagement, even though it's filled with misandry.
Honestly, the setting is about as believable as the hentai-land equivalent of national impregnation laws. Which is to say, absolutely unbelievable because no sane world would allow it, and even in an insane world, there would still exist more than enough opposition to push back against it, and it would also never be able to achieve global scale where those rules aren't just centralized within a single nation, but somehow is applied through all nations of different creed, philosophies, culture, values and base religion.
Which is to say. The answer in the end is...