Kizaru bro, without wanting to provoke and speaking with all sincerity, he's just looking like a doormat at the moment, linked to a mission and fixed on it, a mission given by BOSS Gorosei, that's it... He's secondary here, which is why Oda had Luffy put him to bed so early.
Imagine Kaidou running all over Onigashima saying: I need to carry out my mission ordered by my BOSS, that's so pathetic.