It's not rare for envelope protection systems on commercial aircraft to have some sort of override. That it's required to be present in normal operation to pass

It's not rare for envelope protection systems on commercial aircraft to have some sort of override. That it's required to be present in normal operation to pass certification does not mean that the plane is suddenly illegal if it's switched off under abnormal conditions. Pilots do not typically override safety systems that are functioning properly because they don't want to die. Airlines do not order them to do so because they don't like fines, plane crashes, or being ordered to shut down. It's not like turning MCAS off makes the plane go faster or burn less fuel. Nobody would turn it off unless it was malfunctioning.