I mean, it's been a few decades since the last human male has died. There are androids everywhere, some obviously malfunctioning... and then you have a crazy inventor who sent an actual robot knight to school. Given her eccentricity, the first conclusion is that she's having fun doing crazy--and likely illegal--things as usual (that's a recurring thought shared by many characters). That's pretty much what saved MC many times. If not for her reputation, he'd have been suspected much earlier.
... I agree there will be some plot contrivances but that's the norm when creating an improbable scenario like "what if all men died?", especially if it's a story with porn elements.