The torture and castration of Theon Greyjoy doesn't offend you, but the idea that a bad man might rape his wife does?
Like the castration of Theon, the message of Sansa's rape is simple: rape is horrible, one of the worst things a person can do to another. The show has had horrible people being horrible since it began; it is not called Game of Kiddie Chairs. The goal is to win an iron throne made from swords. What show did you think you were watching?
I realize that readers brought up on romance novels would expect Ramsay to be defeated by a virtuous knight or to fall in love with Sansa and be transformed into a husband who is worthy of her. But this ain't that show. The one thing you know is bad things happen to good people. Your only consolation is knowing that bad things will also happen to bad people. Sansa undoubtedly survives her marriage to Ramsay. It's not likely that Ramsay survives this season.
People obsessed with male and female gazes should note that the scene ultimately has a male point of view, but that POV is not Ramsay's thrill in using Sansa, but Theon's horror at what's being done.