Why is there no alert if shutting down a running engine during flight? In reference to Flight 235, there is a lot of speculation going on today, and since the flight recorders' data indicate that the running engine was shut down manually, everyone is suspecting that probably the pilots made the mistake to shut down the running engine instead of the faulty engine to attempt a restart.

If that was the case, why can't there be an alert to warn the pilots that they are shutting down the working engine?

In the software world, we attempt to create so many fail safe situations to avoid letting users mistakenly take an action which will kill the process, why can't that be done for a multi-million dollar aircraft where so many lives are at stake?

P.S: I know these are all theories and not any official crash investigation reports but I am curious as to how such suggestions can even be made? Even my radios for radio-controlled airplanes provide many fail safe features.
Because in an emergency situation you do not want to stand in the way of the pilot.(*)

Whoever designs the system knows that it could fail and it also knows that there are two pilots in the cabin. These pilots have been trained to deal with the emergency, have spent hours and hours in simulators to be ready when something happens, you do not want to treat them as clueless users, you want to treat them as professionals that are doing their jobs.

The system told them that there was a failure, if it would have been a black/white decision the system could have already shut off the engine, but it did not: it lets trained personnel to asses the situation and act accordingly.



*: as fooot correctly points out, you do not want to annoy the pilots with warnings (remember, you just told them an engine is not working!), they may be tempted to preemptively cancel them, causing them to miss other warnings that are actually important.