Red CoC is for bums that can not make it to WSS like Shanks and Roger or DF merchants like Luffy.
Anyways, I am not sure anymore if these threads are slander or wank.
Its just CoA? Then Zoros CoA is so insanely strong it breaks other peoples CoC. His Ashura cut CoC clad Kaido.
Its CoC? Then Zoro could use CoC since Enies Lobby. Its where he first used Ashura.
I am fine with either, lol.