Including that additional information in their report could have given the technicians a chance to find the real problem, or at least it could have given the next crew enough information to be able to deal with the problem successfully. I find it very strange that they didn't include that in their report.
It is a bit odd to be blaming an aircrew in Ethiopia for not providing information that Boeing engineering already knew! Airline pilots are not supposed to be the testing and documentation department.
This really goes to the fact that Boeing chose not to document the existence of the MCAS system. The behavior that the pilots experienced was impossible in the NG so they used their best guess as to the cause, and as humans do, filtered out information that was irrelevant to the cause. After all, their job is to get from A to B and they are not trained in the art of system diagnosis and documentation. In fact, everything I have read here indicates that pilots are explicitly discouraged from failure diagnosis, which is the justification for why the function of the two cutout switches was changed. To now blame the pilots for an inadequate description of the failure seems contradictory.