#except no

The narrator says clearly that Darcy has always been like this, it isn't a trauma reaction, "He was at the same time haughty, reserved, and fastidious; and his manners, though well bred, were not inviting... Bingley was sure of being liked wherever he appeared; Darcy was continually giving offence." And Darcy confirms this, he's been rude "from eight to eight-and-twenty" The only time he brings up the whole Georgiana thing is to tell Elizabeth about it, he never blames that event for his behaviour.

If anything, Jane Austen was a proponent of "explain but not excuse". Lucy Steele is mercenary because she is barely clinging to her status in the gentry, but she's still portrayed as a villain because the way she goes about trying to secure Edward (and later Robert) is fundamentally wrong. Mary Crawford has a back story full of trauma, she's an orphan twice over, her uncle sounds like a misogynist creep, and yet Austen doesn't accept it as an excuse, Mary must become better to be worthy of Edmund. Willoughby is an orphan, he's in debt, he's made bad choices, but he needs to do better and because he doesn't, he's not worthy of Marianne.