[ColinCochrane]

This is true, but I think the point the parent comment was getting at is that an investigation tends to take a more holistic look at the incident rather than simply assigning blame directly to a single factor. Even pilot error, especially in the context of commercial aviation, is often found to be the result of training deficiencies or cultural issues on the part of the airline.

[FabHK]

Yes, exactly, well said.

That's precisely the idea: if a pilot makes errors so grave as to endanger the aircraft, how come the airline training/monitoring in place did not pick up indications earlier?

The people that helped overcome the "pilot error, case closed"-mindset must be thanked (among others) for making aviation today as safe as it is.