"[Lubitz] never applied for a higher medical class; he never needed to do that and why would he? Getting the FAA class 3 medical is the normal case for this type of flight training, and there is no reason to get more (and pay more) if one plans to work in Europe as a pilot."
It might be normal for that particular school, but I can assure you that anyone who is at all serious about a professional career in the States will start with an FAA Class One medical just to get that Student Pilot's license, as I did. Getting a Class One, not a Class Three " ... is the normal case for this type of flight training .... "
You only get a Student Pilot license out of the exercise, true, but you know then that you do not have some condition that will bar you from later exercising the privileges of a professional license requiring a Class One. The small difference in price is not a factor for someone who is going to be taking up a course of training that will take years, since it gives assurance that all that hard work and time spent should pay off in the end with a job as a pilot.
Looked at in a certain way, for the FAA to say "Okay, here's your Class Three to fly as a student pilot," and to leave it at that is "passing the buck," leaving it up to the LBA to have approved Lubitz for a Class One despite his history of severe depression. There the FAA was ignoring the obvious end goal, Lubitz holding a Class One to act as a professional pilot, to merely look at the presumably lower FAA requirements for a Class Three to act as a student pilot.
One prerequisite for doing the course for the ATPL writtens at London Met about ten years ago was holding a valid Class One medical, including a medical examination from the British CAA itself, not just from a normal medical examiner, if I remember that correctly. Why did they require me to hold a Class One medical, just to sit in a classroom to study for some writtens?
We might not be having this discussion if Lubitz had been required to get an FAA Class One before going solo in the States. Who knows?