X-thriarchy doesn't mean that the X gender can act as it pleases. It generally only means that leadership is restricted to X gender. Just because it's a matriarchy doesn't mean the society doesn't have strong expectations of women. I mean... Surely you've heard of such ideas and opinions that a boy needs to have slept with a woman to become a man?Menstruation, pregnancy and birth are also occasionally seen as 'truly feminine' things even in modern feminism which kinda stings for maab trans women.
The world at large isn't really relevant. This is a story the author is writing, not a fully developed setting. Considering it's limited scope it's not really relevant to spend time creating a detailed setting.An oppressive patriarchy and matriarchy can be just as restricting to both the oppressive and the oppressed gender.
Finally. Comedy is used to lighten the mood and give some breathing room for the reader in an otherwise unpleasant thing to read. Guy's pedophilia and his choice not to act on it is also not the sole defining feature of the character.