They thought the bald dude with a giant sword had was some chuuni carrying a fake katana, like, LOL NOPE, they're the highest authority in the WG.
Kizaru HAS NEVER acted like a suck up before he talked to Saturn, and here he is, an Admiral, SERVING A MEAL TO A GOROSEI. That told us all we needed to know, I can't believe people thought the WG's highest authority under Imu was weak. ESPECIALLY AFTER COBRA DIED.
Even as Fleet Admiral, Akainu speaking to Kizaru felt much more like comrades conversing, than Kizaru feeling like he was below Akainu in strength and status. Kizaru obviously respected him and was going to listen to what Akainu told him to do, but, Kizaru didn't act subservient.
Kizaru knows what crossing the Gorosei means. Nothing good.