The same reason they had men in drag playing the female roles in plays in those days.
Women weren’t people. They didn’t get to be singers or actors. They were property that worked in the kitchens and went places with their husbands (if they were lucky).
Of course in hindsight it seems obvious to say “why didn’t they just have a woman play the female role in the play?” but that’s just not how society worked at the time.
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