you do not seem to grasp just how serious an incident this was
Aircraft, I'm afraid that it is you that doesn't grasp the incident.
Yes, the crew likely made an error. Yes, it was caught by the configuration warning horn. Yes, the crew corrected their error and continued.
My boy, the system worked as advertised. The QAR WILL have captured and flagged it, but I guarantee you that the crew WILL have self reported.
How do I know? I fly 737's. Whilst I haven't personally seen this one occur, I have seen plenty of other things which would probably have you sh1tting in your nappy.
So pullleeease don't get on here and lecture professional pilots about their moral responsibility. They are fully aware.