Except that's not what the sniper said Zach, they said they had been told the suicide bomber was not arrested to protect an asset, and that they could not take a shot.Basically, it comes down to PR.
"Marine starts firefight and kills innocent local" and it leads to then assaulting the airport and doing worse.
Sadly we will never know
It was not said "no, because fire fight might ensue", it was "i don't know why you cannot fire, let check up the chain", and the answer never arrived before the blast.
Stop making excuses for military fuck ups of this scale, admit someone, or multiple someones, effectively murdered those troops and civies by not allowing the sniper to fire.
Whoever made the call needs to be frogmarched in front of Congress and put on a public court martial trial.