How you could come to this conclusion from that statement I'll never understand
The world doesn't revolve around Zoro. Zoro is Zoro and Sanji is Sanji. Both are regarded as Luffy's vital pair of wings.
This statement puts emphasis on the burden and responsibilities these two characters in particular shoulder for the crew and also their special roles in the crew even in comparison to the other members and this time it isn't just Oda saying it in an SBS but Robin a crew member actually putting Sanji on a pedestal with her own mouth.
As as Sanji fan, even though this much is pretty obvious given how Oda has written those two, gotta say it feels fcking fantastic for Oda to have Robin actually call Sanji one of Luffy's wings in the manga and I can't help but be excited about Sanji going forward in this arc
. Zoro being the other wing is cuul and that much is fairly obvious considering Oda has literally said the same ting in SBS before but it is not what it is important here.
Also if anything Oda bringing up how Onigashima currently views Sanji as laughing stock is a good ting from my perspective particularly if you put it side by side with Robin calling Sanji one of the wings of a Pirate King. All I know is Onigshima is finna be shook in the next few chapters and I'm looking forward to it