Not to suggest that this detail you're calling attention to is inaccurate, or that it had NOTHING to do with how things played out Still though I think it's pretty cut and dry why the fallout was what it was. The show basically spelled out the reason for the fallout. There's the scene where he's talking to his father and his father explicitly shouts (This is a paraphrase) "Do you realize how stupid that was. You punched a guy over comments about how you're the Princesses actual baby daddy. Now that you reacted that way, when everyone asks why, you've called attention to that issue" His father is not shouting at him about the power structure of kingsguard vs. goldcoaks.