I don't see how anyone can defend Zoro's word (again shown as heartless bastard, as usual since post -TS really) by using the imbecilic things he said on Zou :
He was wrong in Zou, he'll be wrong here, again.
- Not pick a fight with Big Mom ? Already done at Fishman Island were she never said she was okay with the treasure, only that her wrath would be directed at the crew. There was no proof she wouldn't have made a beeline for them as soon as the wedding was over.
- They had all the tools for an infiltration : Pekoms, Robin (realistically she made a lot more sense going to WCI but had played her part in the second half of Dressrosa), the element of surprise and the knowledge that Sanji was pressured into this situation and thus would probably want to return to them.
- Kaido wasn't actively searching for them because they were still fucking small fries to him. He could have sent King or Queen and a part of his crew to hunt the strawhats. He didn't. He only got Jack retrieved in the sea and didn't even try to hunt down Zou again.
- Like it or not, Sanji is the third strongest member of the crew, and they needed him to deal with Kaido. Giving up on a powerful fighter only because some dude doesn't like said fighter is dumb as hell.
He was wrong in Zou, he'll be wrong here, again.