Thing is the program is not even a sex program. The episode did sort of cheat by just showing that one moment. If she actually watched the whole program through she would realize she was getting mad at him for no good reason. Granted she does know he has romantic feelings for her so it doesn't take a genius to understand how that and masturbating go hand in hand(pun intended.) but at the same time that stuff should be private. What people are masturbating to on the holodeck during their private time, is nobodies business.
