A bit LTTP but whatever.
A lot of the problems with the scene have already been touched upon, but what makes the scene even more troublesome from a feminist point of view (apart from everything already mentioned) is the fact that Sansa isn't shown. Okay, they ruined the character, made a scene that makes no sense besides shocking people, but even during that scene where someone (a female person) gets raped, what do we see? Reek's face. Reek is suffering, it's so hard for that man to watch what is happening before him, let's all feel sorry for Reek and not show the gruesomeness of what Sansa is going through. The male perspective is shown to be more important, which ruins the impact the scene could have had (it's still a bad scene and completely unnecessary).
I wasn't sure if this was already mentioned, the thread is too long, only went through the first few pages, sorry.