There is zero evidence that Garp would defeat Akainu fam. There is nothing that says "Garp defeats Akainu 10/10 times." At all.And then Coby stood right in front of Akainu. The stupidity is fantasizing or speculating that Garp would not be able to put down Akainu.
So no, you don't hear what is written, you read it. And what I read was and is completely stupid.
Coby standing in front of Akainu means absolutely ****ing nothing since he was about to be killed had Shanks not saved him.
Your statement that Sengoku wouldn't have stopped Garp if Garp lacked the ability to kill Akainu makes no sense because if Garp lacked the ability to kill Akainu, Sengoku would need to stop him from getting himself killed.
The scan of Sengoku stopping Garp doesn't prove anything.