Well, just as I don’t want to yuck anyone’s yum, it’s awful hard to yum someone’s yuck, you know what I mean?

Speaking as someone who isn’t super into shipping, given how much really questionable/problematic sexuality that there is in ASOIAF,at least the relationship might be between two people of basically the same age, involve enthuastic consent, and lack the toxic dynamics that relationships founded on direct defiance of the Westermark effect seem to have. 

And hey, we’ve had uncle/niece relationships in ASOIAF (looking at you, Jonnel One-Eye and your larger dynamic of trying to reconcile the competing claims of the daughters of Rickon son of Cregan by way of Arra Norrey with the sons of Cregan by Lyanara Stark), so at least there’s gender parity there. And hey, when has uncles and aunts marrying nieces and nephews ever caused a problem?

To answer your second question, I think it’s a cultural thing, a deep memory of the need to preserve the dragonrider DNA that ultimately comes from the strange blood magics that fused the ancient Valyrians to the dragons. That’s right tumblr, Dany’s a cryptid.