This has been flogged to death on another thread.
This is an AAIB report not a medical report. There must clearly be concerns that pilots are getting on the line when their fear of certain aspects of flying have not been picked up during training and/or their training has left them so deficient in dealing with, in this case, windshear. There is no hard evidence in the report of a 'medical problem' nor do I see anything that would be screened out by a mental health examination during the initial Class1.
Of course in the good old days of BA scholarships the individual would have faced stiff competition and likely not succeeded, but nowadays it is more self selection as long as the trainee can afford o pay for their license.