Funny thing is, no one programmer can know all languages and systems, and with a short consult into an aspect of a system they're unfamiliar with, would be unlikely to give more than general advice.
Sounds an awful lot like the situation every GP is in... no one human can know everything about the body, so there are GPs that legitimately can't diagnose you.
On the other hand, the person with a particular bug to troubleshoot in themselves has all the time in the world to become their own specialist and do the knowledge synthesis that the generalists don't have the scope for.
I've read way more about my relatively common condition than anyone but the specialist I'm seeing, and I've come up with some things that he was not aware of in the process. Once down a certain condition's rabbit hole, the patient/specialist dialog really should be a give and take.