Theres is the editor's note for chapter 1022, that also mentioned the wings
That statement settles up one of the most loved dynamics in the manga, it completes the story as a whole, it isn't some random stuff just thrown there for no reason.
Zoro and Sanji are one of the main and most famous characters right beneath Luffy, the main protagonist, you want people to simply ignore that?
And besides, volume 102 also mention the wings in action, the whole marketing around the release of volume 102 was literally all about Zoro and Sanji and the portrayal the manga has build for them for all these years.
They even made a quiz about how much do someone elses "brain" thinks like Zoro or Sanji