There's Kurenai's disgusting ending with its whole "child abuse is okay if a minor goes along with it" thing. It's one of the worst and most offensive endings I've ever seen in fiction.
I didn't like the ending either but I'm pretty sure the point of that was Murasaki electing to subvert the traditional system on her own terms using her experiences with Shinkuro as a stepping stone, but then maybe my memory is faulty.
Not that trusting a seven-year old with the responsibility of inserting herself back into a screwed-up situation to fix it without immediately being taken advantage of sounds like an idea anyone should roll with.