I 100% agree that that scene should not have been done in that way, but GoT and now HotD usually put spectacle above logical action and it fucks with the story. I get why she doesn't kill them (because she doesn't in the source material) but really she shouldn't have even gone there, just escaped and been done with it.
The why make up all these lame excuses for why she didn’t burn them down that make zero sense.
You spent post after post defending the character’s actions and there is no defense.
I think because the fanboy inside you can’t admit the medium you love so much could make such an error so your brain rejects it or at least tries to reconcile it. Free yourself from this bondage and live amongst those who value the truth.
The writers screwed up massively and it damaged the character.
I think in the end, the fact that they are her brother's children is what stops Rhaenys from torching the lot of them. The dragon killing innocent townsfolk in the process could also be setting the stage for an anti-dragon revolt later on. But, overall I agree with everyone else, it was kind of a pointless spectacle that caused more frustration than applause.