Saying "he could have left" in this situation, after being shown exactly how that would have/did go down, is like camping out in front of your ex-girlfriend's house with a baseball bat, then telling the officer you didn't beat her and thus did nothing wrong. Except the whole world can see you totally did beat her when she finally left the house.
As I said, framing it as that simple of a choice may lack some nuance in describing the pressure he was under. But it is factually true that he was not forced to stay in the conditions which are being criticised. Some would also say that the nature of the conditions was somewhat of his own doing, since the relationship with the embassy is well documented to have deteriorated greatly over time. I can't vouch either way, and it seems people are downvoting normal conversation so I doubt it will be productive to continue.
He has always been free to face his accusers.