I agree - being a pilot and a programmer is neither a necessary nor sufficient condition for being able to diagnose and solve an issue in a system as complex as a modern airliner. In fact I don't think any individual is capable of doing so on their own; maybe the sole exception being someone like the engineering lead of avionics for the 737 Max, who is probably not a pilot, and probably only a programmer in so far as it was a component of their engineering education.