Arya's Most Unhinged Crime Was Completely Ignored By Both GoT Characters and Viewers
The Red Wedding was a horrific bloodbath and left a huge scar on House Stark.
It only makes sense that the Starks hated the Freys after that, but only one person actually did something about it.
Arya Stark butchered the entirety of House Frey in her own brutal and unhinged massacre, avenging her family and making sure this House disappears for good.
She leaves a few survivors and tells them that she's from the North, and the North remembers, effectively letting at least her allegiance known. Oh, and Edmund Tully is now free.
On the Westeros political scale, this is a massive event: an entire House is completely wiped out. A House that's allied with the Lannisters. A House that controls a crucial strategical location.
And NO ONE ever brings it up later in the show! Well, not exactly no one.
Cercei and Jaime Lannisters mention it once in a private discussion. But they act like they don't know who's behind this massacre, and don't exactly do anything about it, even though this suggests dramatic consequences.
Other than that — nothing.
There's no talk about the butchering of the Freys, there's no geopolitical effect, and everyone effectively ignores that this even happened.
Even Arya herself acts like nothing happened when she comes back to Winterfell. Wasn't she supposed to at least mention it to Sansa?
Something like "Hey, I avenged our family, and maybe you should send some people to take the Twins while it's still vacant to improve our position" would've done the job. But no. Nothing.
It would've also been a very valid reason for the upcoming tension between the Stark sisters — Sansa being terrified by what Arya did and has become, and Arya being all righteous and stubborn about doing what she believed to be right.
Instead, this happens for a far less logical reason, which is rather underwhelming.
It seems like the Starks don't care that they were avenged, the Lannisters don't care that they lost a strategically important ally, and the other Houses don't care that one of their rivals was destroyed and there's a sweet vacant spot in the Twins. Everyone just rolls with it as if nothing really changed.
Also, even though there were too many deaths all across the Seven Kingdoms at the time and that made calculating the life-death balance quite difficult…
Do you really think Jaqen H'ghar would've let Arya get away with this massacre?