Why wouldn't Boeing like the identification of the root cause?
Because that root cause might be due to Boeing's offloading too much systems design and manufacturing responsibility onto subcontractors. And the fix might reverse Boeing Corporate's current policies in this area.
I was working there in the 1990s when the FAA uncovered major QA problems with aircraft subsystems. The FAA finding and remedy (which I was involved with) was to clean up the functional testing process. And that involved holding design engineering's feet to the fire to take their (FAR mandated) responsibility for overseeing that testing seriously. Boeing management screamed like a stuck pig, but made the required process changes. It was either that or lose their manufacturing certificate. The changes interfered with Boeing's strategy to push engineering tasks out to subcontractors. But only for a while. By the time I left, they were back on track outsourcing everything.
If current problems can be tracked back to a lack of end-to-end oversight from design engineering through to manufacturing and quality control, Boeing might be stuck with some major reorganization.