Things Rosemary Sutcliff Did Not Make Up

In googling for something quite other, I found an old discussion of Sutcliff's Sword at Sunset (a book of which I am unreasonably fond), in which the commenters lay into the author for having written on a topic they found distasteful.  Incest.   Yes, they felt that including incest in an Arthurian story was something that rendered the whole book unreadable.  

 I assume they haven't read Malory.  Good grief.   I then became annoyed, and wished to share my annoyance with The Internet.   Then I had a long agonised internal debate with myself whether to use my 'history' tag for this post.  This was quite ludicrous. I am therefore tagging it 'loons' and including myself in the tag...