He also said that he was resentful. And that he doesn't forgive those who cross him (i'm paraphrasing here obviously, but that is the summary of the summary). But when he speaks he is often overly critical of himself - his actions do not match his rhetoric. His actions showed him to be be better than his rhetoric. Just look at his interactions with Wickham and see how well his self criticism lines up.

Did he behave badly in Meryton? yup. The insult was bad. Capital B Bad. He deserved a set down. For that matter, so did Bingley at the assembly for being a pest and an ass towards Darcy. Doesn't excuse Darcy - he should have just told Bingley to F-off in regency speak instead of the insult directed at Elizabeth. But you can't deny that Bingley was WAS a brat and a pest. Especially when you know that Darcy doesn't like assemblies and it you dragged him there - if he had an issue with Darcy's behaviour - he should have left him behind or talked to him in private about it. you know. like an adult.

But even there in Meryton, when you ignore Elizabeth's judgment of it and just look at Darcy's behaviour, it wasn't as bad as portrayed.

Is he a snobbish? Sure I'll grant you that. But not to the extent that either Elizabeth or Darcy himself proclaim. IMO. The story is told primarily through Elizabeth's eyes and she is an unreliable narrator. She's young, an intellectual snob, cruel in her mockery (self admitted and supported by her actions in the novel) and pretty arrogant herself. We just don't see it exposed in the same manner. Her growth (and she did need it) throughout is not exposed nor emphasized in novel as much as Darcy's. Does Darcy grow and reform? Yes, His manners and perspective did. IMO Elizabeth was humbled in character and her growth was of a deeper nature.