Kaido is Luffy's opponent and Zoro knows that, if Luffy wants a 1x1 fight, Zoro won't intervene.
Zoro apologizing to Kin'emon only shows that he cared about the plan, PLUS, he attacked Orochi without thinking twice, and still he had a someone trying to make him stop.
But either way, the badass had his moment in which is a parallel with Luffy and Oden. I'm telling you man, MONSTER DUO IS ON FIRE during this arc.
:cheers: