In One Piece, why do the navy call weak executioners to carry out executions?


In _One Piece_ , whenever strong people are executed, the executioners in
khaki getups are the ones to do it, even though they are much weaker than the
people the execute.

for eg:- At Marineford when Ace was getting executed, the executioners even
got injured by Crocodile and they still called extra executioners after this.
Why didn't Sengoku or anyone else do it? The new executioners weren't even
strong enough to stand against Luffy's haki.




For an example :

When Ace was being executed at Marineford, the Fleet Admiral, the 3 Admirals,
the Vice-Admirals etc. were placed at strategic locations for the upcoming war
with the Whitebeard Pirates. The Navy knew Whitebeard was gonna make a
fantastic entry into the battlefield(not HOW he would enter Marineford). So,
it was necessary for all the high-ranking Marines to be ever-ready for war.
Naturally, the task of executing Ace was given to the weaker Marines.

This policy is followed in all the Navy executions to be prepared for a fight
with the Criminal's NAKAMAS

