Why.
No, seriously, your reason is just plain... why.
Urg, why do people INSIST on making everything liberal friendly around here? I wish people could really just accept that Medieval Europe was indeed sexist.
Grumble grumble.
I'm an antifeminist (that is, I think the movement has run its course in the Western world - I would have supported the movement up until several years ago, but no more) and also very concerned with historical accuracy, but I still support mods like this (if not the name - if a title "misogyny" is not OK, then neither is "misandry" but that's debatable and beside the point).
I posted many times in support of enatic succession, not because I wanted to see a liberal-friendly Medieval world, but because I wanted the option to create unique stories where a powerful queen might in one kingdom turn the tables on men, as that would be a remarkable challenge (should be VERY hard to do).
I like this option because I like the power to do things historically near-impossible to do, but also with a high level of challenge to reflect that.
In the case of this mod, think of it as alternate history. What if the Roman Empire in its early days had a unique event which allowed women rulers, and this later transferred to female-only rule? What if Roman sexism had become veneration for women?? Unlikely, but an interesting concept to explore nonetheless.