The line between depicting something realistically and appearing to endorse or support it is really thin when it comes to rape (and by extension, violence against women).
This could be grounds for a separate thread, but isn't it better than the alternative? I read a lot of Japanese stuff, so I've read way too many stories that present something that's obviously rape, but soften and excuse it, even having the victim start to enjoy it halfway through. I'd much rather read a story where rape is presented as something horrific (and that's how I tried to portray it in Eternal.)
Actually, maybe this is related to this thread after all. Wouldn't you rather read a war story like The Forever War, where war actually feels violent, than one where it feels like a great big game? Or if a story involves drug abuse, isn't it better to be frank about the cycle of addiction? I don't know where the line is between dark and grimdark, but for some subject matter, going dark just means following through and being frank about the elements you've introduced.
Edit: With that said, I should concede that there are times when portraying something feels like endorsing it. I'm not sure how many people here have read Fifty Shades of Grey, but the male lead rapes the female lead--and I don't mean anime rape, I mean actual graphic rape. It's still presented as a romance story afterwards.