So you're saying woman were immediately made slaves in the Roman Empire and treated as less than dir.
They weren't made slaves in the sense of being captured then bought and sold at a market, but they were the "property" (legally) of their father until they married and then became the "property" of their husband, were expected not to leave the house, were not allowed to possess money of their own nor have any independence whatsoever, could not go anywhere without being accompanied by their father or husband. It might not be outright slavery in the sense we immediately associate with the word in modern terms, but it was hardly an enlightened time for women.
Women did not even get an official NAME as individuals, they were named after their father - so if a man called Julius were to have 3 daughters they would be named Julia Prima, Julia Secunda, and Julia Tertia (Julius' first daughter, second daughter, and third daughter respectively).
All I am trying to say is don't make out that ancient Rome was any better than it was, because it was pretty grim for women and worse for slaves. And it doesn't surprise me any that someone in the Fallout world basing his morals on ancient Rome would be disparaging towards women and in favour of slavery and brutality.