Zoro does only follow orders that make sense, explicitly shown several times by now, and also threatened to kill luffy if he ever went against his dream.
Of course the gorosei won't fire fujitora. What is an official slave for them? Everyone's a slave for them anyway. Freeing the slaves only pissed off their owners, the fodder CDs who nobody cares about. Do you know the organizational effort to find and hire a new admiral? They can barely find a couple df merchants like broccoli, they won't drive away their personnel so easily.
I’m not talking about Zoro but you with that mentality mate
But now that you mention it it was Zoro who was on his knees like a beggar
Gorosei can’t do shit to any Admiral
Akainu walks into all 5 insects lights a cigar and threatens them to their face
Fujitora frees slaves in Mariejois
Kizaru commands more authority as seen vice admiral doll, and refuses to proceed with Saturn’s plan and does things his own way
Aokiji would casually leave HQ and go on strolls while the Gorosei bitch and moan about his carelessness
They can’t do shit