When you play the Game of Thrones, you have to keep in mind you either win or you die, and you have to be prepared to commit the most heinous crimes to sit on top of the Iron Throne. But some are considered more undignified than others, and kin slaying ranks amongst the top.
Killing one of your own is strictly forbidden in Westerosi culture, and if you do, you are branded as cursed, and there are consequences, as Game of Thrones has often emphasized. But House of the Dragon seems to be overlooking that concept.
The Greens are the biggest hypocrites in the realm
It has been well-established in Game of Thrones that kinslaying is one of the biggest and most looked down upon crimes in Westeros. Even great kings couldn’t get away with it. From Maegor Targaryen to Robb Stark and Stannis Baratheon, everyone who struck their own people was criticized and died horribly.
These customs have taken a backseat in House of the Dragon, where the Green faction is using it as their own weapon to justify the warpath they have taken against Rhaenyra. Aemond killing Lucerys should’ve had grimmer consequences on the former, starting with imprisonment. But the Greens know Aemond and Vhagar are their greatest weapons in the upcoming Civil War.
Luke’s death is taken very lightly by the Greens, except Alicent and Otto Hightower, the latter even sends a letter of apology to Rhaenyra, but we all know that is not enough. But when Jaehaerys is killed by Daemon’s assassins, Rhaenyra is branded as a kinslayer, putting her on the same pedestal as Maegor.
However, the Blacks themselves are not much better in this regard.
The Blacks are following in their rival’s footsteps
While it is true that the Greens were the ones who initiated the Dance of the Dragons, the Blacks are not saints when compared to them. When the news of Lucerys’ death reaches Dragonstone, and Rhaenyra happens upon her son’s dragon’s remains, her first thought is kinslaying as well.
Though she has valid reasons, kinslaying is always looked down upon and should have been raised as an issue by at least one of the council members, just like the Northerners did when Robb Stark executed Rickard Karstark. But everyone goes ahead with the plan.
We know how the Dance of the Dragons ends, and it is as grisly and bloody as one can imagine. So at least we know both the factions were cursed from the beginning. The moment you turn upon your own blood, the new and old gods of Westeros will not spare your soul.