Well... Greenbull is also an admiral an he was trying to do the exact same thing he's supposed to prevent... Just because Wano isn't part of WG so... No, Admirals are full of shit, I only sorta respect Fujitora I guess he doesn't like being part of a the huge mafia WG is and is trying to change it
Akainu killed O'Hara survivors even before he was named Admiral. He's just that kind of dog, whatever WG wants, he delivers. A violent full of fear dog. But still I would like to know if he has always been like that or something in his past changed him.