Why does he deserve benefit of the doubt? It's well beyond doubt. I don't have to have met him, I saw his uniform and read about a fellow Marine's encounter with him. That's more than enough proof to me.
Google Stolen Valor and then go to images. There are countless stories of these idiots out there.
Compare those clowns to how this retired Master Gunnery Sergeant looks:
Only one idiot now and it isn't him.