@SLFplatine
A lot of discussion on the post 9/11 door that kept the pilot out of the flight deck but really none the discussion on the German medical confidentiality regime with the severe legal consequences for the breach that failed to keep the FO off of the flight deck in the first place. Just an observation.
So your thesis is that had the German medical system not kept the pilot's confidentiality then he would have been prevented from flying. You may be right, but you must also accept that this might have prevented him from presenting his problems to the doctor in the first place, or going to an independent doctor instead.
I am concerned with the future, which means accepting that a) there will be a set of positive and negative aspects to every policy decision, and b) one has to talk in terms of the average result rather than focusing on any one specific incident.
We will never know if FO would have presented his problems if the German system had been different, I just think it is highly probable he would not have done so if he knew it would not have been kept confidential.