I agree, and it's not so much about Jon & Daenerys, as the fact that everyone makes a big deal about their aunt-nephew relationship, and no one notices that Tommen-Margaery is also aunt-nephew, and way creepier, even if not incestuous by modern terms. OTOH, it was medieval attitudes and post-medieval, that a king's marriage was called into question because of his wife's prior unconsummated marriage to a blood relative.

And it's not my specific morality that says that marriage featured an older, sexually inexperienced party using that experience to manipulate a barely (if that) legal spouse and emotionally isolate him from his family, to the point that if you disregard the books, Cersei's apologists are not all that wrong on the show. Most of what she does IS in defense of her children, and trying to maneuver in a system stack against her, often randomly. Olenna actually says to her face that she's the most horrible person ever, except Cersei isn't the one in that conversation who broke the laws of hospitality to murder the other's child by poison.

My moral issues with the show have little to do with its violating the code by which I live, but the fact that the code is different in every season and every plotline. One minute the Sparrow all deserve to die because homophobia and meanwhile, the writers have Loras being a huge sissy who is more of a bridezilla than his fiancee, and a slut who blabs family secrets to a random hook-up, and lacks the emotional control to lock it down when his one-night stand testifies against him on bullshit evidence. "Hate them for bigotry, and giggle at this stereotype!" is the show's morality.