Masterbation only partially placates a man, as the emotions from lack of progeny and pair bonding are still present. Receiving sex placates him some more (the Enkidu gambit sort of works but I don't believe it fully does), while achieving his biological imperative of progeny fully placates him until tyranny endangers his own.

They are using the medical industry as a prop. Tyrants fear abstinence in single men because that unreleased sexual energy has to go somewhere and will be harnnessed somehow. It can cause him to turn to criminal action, Or make moves to disrupt and change society. I would say they fear bachelor volcels the most (claiming "incels" are a threat is just a cover) because such men may either acquire resources to which the government believes belongs to them alone and fear it being used against them, or such men geomaxx and the government loses another tax slave for their house of cards.