It kinda sucks that Zoro will never find out about what happened in Whole Cake Island, the part about Sanji beating Luffy. Only Nami, Luffy and Sanji know that information, and all of them won't share it with Zoro. I would love that see that interaction, i think it would be really tense and interesting, while at the same time picking a setup from Water 7.
I pretty sure Oda knows that if Zoro was privy to that information, the crew would have a pretty serious fight.
Just think about it. Zoro is a lot more open with his respect and caring nature towards Usopp than he is with Sanji, remember how he almost cut down Nami when she said she killed Usopp back in Arlong Park, and even tho Zoro is annoyed by Usopp's coward side, he also respect his braver moments and his sniper skills. Despite all of that, Zoro was still very strict about Usopp's decision to challenge Luffy and then leave the crew, he respected the wishes of Luffy and the rest of the crew that wanted Usopp back, but he determined he would only accept Usopp back if the first thing that came out of his mouth was an apology. Thankfully, Usopp didn't disapoint Zoro and their friendship is completely restored.
Now think about how Zoro would've reacted learning about what Sanji did, especially taking into account how Zoro shows a lot less care and respect towards Sanji, at least openly, we know Zoro does care about Sanji.
The Sanji situation was a lot worse than Usopp's IMO, first Sanji left the crew, Zoro knows about this part already and knows Sanji did it because he didn't wanted to put the crew in danger, but Zoro still was a little bit annoyed about that. Now we enter into the "fight", after Luffy went to save Sanji, Sanji beat the shit out of Luffy, and it wasn't even in a fight like Usopp, it was a one-sided beatup from Sanji torwards his captain. Then, later on, Sanji just wanted to come back into the crew without even taking much responsability for what he did, not apologizing or anything, and Luffy didn't care about it (just like he didn't with Usopp), but even Nami gave Sanji a cold shoulder in that moment (remember Nami was one of the few who was really open to Usopp coming back and didn't care about all that stuff, Nami is one of the most forgiving out of the Straw Hats, she forgave Jinbei!). To top it all off, all the three things that made Sanji do everything he did in WCI were pointless, first the crew was going to rush to save him anyways, so they would be less in danger if Sanji had stayed with them, second the Baratie cooks were threatened, but for all we know they are all safe and sound, even after Sanji escaped from the wedding, seems like it was a bluff, and finally the bracelet bombs put on his hands just completely disappeared, so basically Sanji did all of that, put the crew in risk and beat the shit out of Luffy for nothing, forced drama.
So if even Nami didn't take that shit well, how do you think Zoro would take it?
I'm pretty sure Zoro would make Sanji ask for forgiveness to the whole crew like Usopp or ask Sanji to leave the crew. If neither of these things were realized, Zoro would've left the crew, just like he said back in Water 7.
And also, think about how hypocritical it is from Sanji's POV, because Sanji was the only one that agreed with Zoro back in Water 7 in relation to only allowing Usopp back into the crew if he asked for forgiveness, but when it comes to himself, he acts like nothing happenend, it kinda pisses me off to be honest.
Anyway, just wanted to get this out of my chest.
Fighting fodders which hardly matters and boro breath. Still had enough strength to perfom totsuka paradise.