This post is kind of uncanny because I was just thinking about something similar, partly because of this secret. Re: this issue in particular, I think liviapenn has already articulated a lot of the reasons that there's an issue with rape in fiction, and having this conversation in relation to a particular character is in some ways a proxy for having a conversation about whether writers are justified in using this trope in the first place, which I think is worth discussing in all of these cases. The Doylist question, I guess. But the question of 'How you respond to these characters fannishly -- either through fanworks or through the things you are specifically rooting for to happen to a particular character -- once the thing has been done and you want to deal with it without excusing it.'

I was also thinking of this more broadly in terms of the idea of wanting a character's redemption -- as I've noticed that a lot of the characters I've grown attached to recently (or, I guess, ever, with Spike still being an all-time favorite) are guilty of things I'm not sure I want the narrative to condone (Regina herself; Faith; Jaime Lannister, of course, comes on the scene throwing a kid out a window; Tom Zarek was a terrorist of some stripe before his story on BSG even started; the major-though-not-main characters I've written a ton about in Fullmetal Alchemist were actively complicit in genocide in the past, which is a thorny issue when dealing with both the fandom and the narrative - it's so easy to go wrong with this story, maybe it's better not to even touch it?)

Then I wonder what it actually means to talk about wanting a character's 'redemption' if you only mean 'redemption for things that I don't really find that hard to forgive' or 'redemption in the sense of the narrative admitting that what the character did was really not that bad and besides it was someone else's fault and besides Snow & Charming/Buffy/the Starks were the real villains and what could you expect my pet character to do'? (Obviously I don't really think the latter attitude has anything to do with redemption; the former is of course completely understandable but maybe should be called something else. Certainly there are canonical 'redemption arcs' that I can't buy into because I'm so disgusted by the initial behavior -- I had this issue with "District 9" if I recall, where the human protagonist starts out by torching, essentially, alien babies, and my brain basically went, "I don't care WHAT lesson you learn from this point" and checked out; whereas plenty of people found the character arc in that movie compelling, it just pushed one too many buttons for me.)

Sorry for excessive rambling, your post was just RIGHT on point with what I was thinking about.

PS: Re: Faith on the BtVS list, a lot of people have also cited her seduction of Riley while in Buffy's body, which the show addresses more as 'Riley accidentally cheated on Buffy' than 'Riley himself was violated.'