Game of Throes

This has been a difficult week for many people who consider themselves to be in touch with bedrock principles of morality, as they ask the question: Am I OK with incest now?
Incest, after all, is supposed to be something we can all agree on. This week's Torah portion takes hot stepmoms off the table: "A man shall not take his father's wife, so that he does not uncover his father's nakedness" (Deut. 22:30). It's repeated and expanded on next week (27:20-23):

‘Cursed be anyone who lies with his father’s wife, because he has uncovered his father’s nakedness.’ And all the people shall say, ‘Amen. 'Cursed be anyone who lies with any kind of animal.’ And all the people shall say, ‘Amen.’ ‘Cursed be anyone who lies with his sister, whether the daughter of his father or the daughter of his mother.’ And all the people shall say, ‘Amen.’ ‘Cursed be anyone who lies with his mother-in-law.’ And all the people shall say, ‘Amen.’

However, the world's most popular television show (though some authorities rule "It's not TV, it's HBO") has a different view on the issue of incest. Game of Thrones' premiere episode ended with a boy thrown out a window for witnessing a man having sex with his twin sister (daughter of his father AND daughter of his mother). And that man, Jaime Lannister, is arguably the hero of the show, or at least the one who has exhibited the most growth over seven seasons. His sister Cersei is now the first ruling Queen of the Seven Kingdoms.
Still, audiences were supposed to be repelled by that relationship. Surely, in the finale of the penultimate season, we wouldn't witness a Game of Throes of passionate incest between our two noblest heroes, Dany and Jon? Well, here's the thing: turns out Dany is Jon's aunt. Oops.
But is it really such a shanda? After all, you've probably heard of a guy named Moses. His parents (Exodus 6:20) were aunt (Jochebed) and nephew (Amram). And the very founders of Judaism, Abraham and Sarah, were brother and sister (Genesis 20:12)--or, at least, uncle and niece (Talmud Megilla 14a). And the Davidic line traces all the way back to Judah sleeping with his daughter-in-law Tamar (Genesis 38).
Still, all that is pre-Sinai. It's not like anyone would suggest keeping it all in the family in a post-Revelation world, right?

Concerning him who loves his neighbors, who befriends his relatives, marries his sister's daughter and lends a sela' to a poor man in the hour of his need, Scripture says (Isaiah 58:9), Then you shall call, and the Lord will answer; you shall cry and He will say: 'Here I am'. (Talmud Yevamot 62b)

I know what you're wondering: but that's my sister's daughter, what about my brother's daughter? That's a matter of some dispute among medieval Talmudists (Tosafot ad loc.):

R. Samuel b. Meir says the same applies to his brother's daughter; it merely mentions his sister because she plies him with words and it common for him to marry her daughter.
Rabbenu Tam says that it is specifically his sister's daughter, for she shares a temperament with him, as we say, "Most children are like their mother's brother."

To make this even more awkward, these two rabbis were brothers. No word on whether they married each other's daughters.
We get that Game of Thrones portrays a fictionalized medieval feudal society. But how often we forget that the greatest Torah minds of the past millennium actually lived in the real versions of those societies.
So if you want to ship Jon & Dany (on a ship), I get it. But let's hold on to the sexual morality we've developed over the centuries, in which consent and respect are the most sacred values. Otherwise, our journey of ethical evolution will end with the realization that we know nothing.