It is perpetuating a lie. I am sure women wouldn't want us men wearing penis-enhancing underwear. What a scene that would make. The guy strolls up to the bar with his blow-up penis. I know what you are thinking.
All penises are blow-up.
He knocks his knees together and inflates his penis-enhancing underwear. The woman at the bar is impressed and like a peacock fluffing its feathers, she flaps her arms to inflate her breast-enhancing bra. Now the woman and the guy talk, dance and eventually go home together. They get into the bedroom. Before long the guy realizes that her breasts are not as plump as they had appeared.