Takwis
very well said. If you have an engine failure there is not much you can do about the cause and as pilot you have to deal immediately with it. So you have to train for that because it might very well happen in your career.
If a computer program makes life threatening control surface inputs due to some false data, first an automated system should deal with that and check the data and system if that makes sense at all. If the outcome is likely fatal you need a DAL-A system. An airplane is a too complex machine as that you can use the pilots as first line of defense against any problem coming up. If it is life threatening and there is no technical line of defense possible then the pilots have to train for it.
Pilots should be the last line of defense.
There is a myriad of redundancy build in an airplane for exactly that reason. You can not take 100% of the pilots capability only to save some bucks on system design.
If you technical can prevent a fatal outcome, you should do with technology.