Hopefully I'm preaching to the choir and the main response from everybody is that this is obvious and didn't need to be said.
I read a few comments from some gross cishets about how angry they are about the female Custode. They prop up the Imperium of Man as though they are some paragon of morality and not the picture of everything wrong with imperialism. Naturally this perfectly moral force would have only men in its ranks, clearly! They don't seem to realize that if women are left out we have a sexist/mysogynist system which is not worth praising, and if they include women then it's the imperialist machine trying to keep up appearances. Frankly, I've always figured the Imperium didn't care about gender or race because everyone is suitable to die in combat and be ground into food for the starving populace.
tl;dr Men are upset that women exist and missed the whole satire
Imperium as a whole don't care but 95% of it is backwater theocratic shitworlds (with the theocratic part immensely resembling the christian realism) based verbatim on various stages of development of real world Earth and i'm absolutely sure they managed to cramp mysogyny in addition to the "everyone is suitable to die in combat and be ground into food for the starving populace." And indeed in the books there is plenty of that, just usually not in the very front of PoV, but in background.