I'm okay with anime depicting heinous crimes such as rape and torture, and social taboos like incest, as long as the subject is handled in a responsible way. It needs to be an integral part of the story or spur some sort of character development, not just thrown in for shock value or to give the writer(s) a flimsy excuse to pull a deus ex machina. I'm of the mindset that content creators and distributors, who hold the ability to reach a massive audience and influence people through media, hold a moral obligation to portray these events in a way that doesn't lessen their impact.
Take Sword Art Online for example. One issue I had with the series was how it seemed to pander to the lowest common denominator with Asuna's rape scenes. Here we have this weak damsel in distress who is established as one of the top players in the game, but relegated to hopeless waifu status for Kirito to rescue, subjected to molestation and rape, seemingly out of left field, just to serve as a twisted type of fanservice and flimsy deus ex machina trigger. Why did Reki Kawahara feel the need to have Asuna raped not just once, but twice, just to drive home the point that women are weak and need a man to protect them? It just reeks of immaturity and poor writing.