It's easy to tell Kaido is acting out of frustration with this rampage rather than out of pure malice. I'm not sure if he sobered up by that point, but if he did, it'd make his current actions more striking. Even though he is a villain in a lot of sense, Kaido's fairly passive while not drunk, and usually retaliates rather than initiate. The crippling reminder of his duel with Oden, stripped of a proper bout with Luffy, and his future plans in jeoprady, he's finally snapped, I feel.