Well, Oda drew him remembering and keeping his promise while King remember and broke his promise of never losing.
I think it would be appropriate to say that Oda is coping instead of Zoro, no? Or some things simply dont count as a loss despite the audience failing to understand it.
The first chapter of a Manga acts as a portrayal of its central themes and core structure, and that is where Oda tells us that a pirate doesn't play fair. If it wasn't important, Oda wouldn't have put it there.
In the same chapter Oda tells us how free a pirate is, and how dangerous being a pirate is.
And who Luffy and shanks are.
Why would Oda be coping? He is simply drawing a prideful character in denial. Pirates don't play fair, a fight is a fight is a fight. And as you well said, Zoro lost on the rooftop. Zoro is simply too prideful that he lost many times, like with Lucci or Ener. There is no shame in losing, Zoro is just too stubborn and prideful to admit that he lost as a pirate many times. And that's the perfect portrayal for him, and how important was to show him bowing to Mihawk on Luffy's behalf.
The person that lies to himself to protect his pride, is willing to bow to mihawk for Luffy in spite of his pride. Great depiction of a character sacrificing himself for Luffy.