It Could Never Happen

When has Hollywood ever let little things like the facts get in the way? Having served with US Marines on a LPD, I agree with your assessment.

I think the story was not meant to focus on these parts. Plus, it's a lot easier to shoot a movie with 300 people rather than 15,000 :)

The focus is on the dilemma. Not that I am disagreeing.

Does it really matter? It was still a fun movie!

So we're all really men of our word except for elizibeth who is in fact, a woman.~Jack Sparrow

If they had fired on the crowd from the helicopters, they would have been better off.

You are correct.

Every US Embassy is guarded by a Detachment of Marines assigned to the Marine Security Guard Battalion. They are called "Decks". A "Deck" can be anything from 12 to 30 Marines commanded by a Gunnery Sergeant or a Master Sergeant and depending on the Embassy. (For example the London Embassy and Paris Embassy are both large Decks. The Istanbul Embassy Deck is smaller.)

You do briefly see a couple of MSG Marines at the Embassy wearing Pistol Belts and carrying shotguns, they are also wearing green cammies. They open the back gate for the MEU (SOC) Marines and Col Childers to come in.

The main concern for the Marines aboard any Embassy is the security of the Department of State personnel and the security of all sensitive/classified documents and gear aboard the embassy. If an embassy is threatened or is being attacked, the MSG Marines have a very specific "to do" list, none of which involves going outside (or firing at targets outside) of the Embassy walls. They are more concerned with destroying all of the classified documents that the CIA Field Officer tells them to destroy.

"Simply Forgot Us"

Added to the goofs already?

You missed the most obvious reason why it would never happen. A Colonel would never have gone on that mission in the first place! Haha. He'd have been back on the ship drinking coffee.

You could add:
6. If there were snipers on adjacent roofs, firing into the crowd wouldn't have silenced them. I expected sam's character to get shot again when he stood up after ordering a cease fire.
7. His character wouldn't have been the only one to begin looking for sniper's locations and wait so long to do that after the first marine was hit.
8. Other marines testimonies would have easily impeached the ambassador's lies, yet none were called for that easy win.
9. A bullet shreaded flag given to the ambassador, would have been good evidence.

The prosecutor said he would only go on good evidence, which suggests honesty - but all we saw of that was his eyes reacting to the most important evidence that went missing too suspiciously (the tape) before he said he received all the necessary evidence.

This movie could have approached being realistic if the plot had sam's character seeing all those women and children firing furiously at his rootop position (while no bullets were striking the wall when he looked) but then the tape was played at his trial to show a different crowd, as it was at the beginning - no firing coming from them. We only saw firing from down there through his eyes, during a stressful moment and after being shot. It would have been both educating and understandable how minds see things that aren't there while under stress like that. Countless reports of troops firing into unarmed crowds involve reports of firing from the crowds causing it.