I think it's just a combination of 20+ years, Ishiwatari just kind of flying by the seat of his pants, and banking on what's trending, honestly. I'm not going to pretend Gear's lore is held together by anything more than duct tape and dumb luck. That said, Bridget is sort of the posterboy for characters the trannies latched onto for all the wrong reasons. They would have had a collective aneurysm if his journey to becoming a man was actually fulfilled, because trannies don't want to jerk off to T&H men; they want to jerk off to either young boys, or girls with cocks. Their brains have rotted out of their skulls from pornsickness and that precludes any sort of writing in the characters they're jerking off to.