FLIGHT #302 - Boeing 737 MAX, FAA Approval Process

My question, why didn't the manual control have enough effect to override the computer system?  Says something about the poor design of the manual control.

"Faulty sensor led to horrifying ‘tug of war’ in cockpit of downed Boeing plane" PBS NewsHour 4/4/2019

Excerpt

SUMMARY:  A preliminary investigation on the crash of Ethiopian Airlines Flight 302 concluded a controversial software system did contribute to the downing of the Boeing plane, and the pilots followed manufacturer guidelines to no avail.  Boeing said it will release a software update to fix the problem, but how did the FAA approve the plane in the first place?  William Brangham talks to Miles O’Brien.