Lets have a go at getting back on track.
The issue is what constitutes admissable evidence. International protocols protect evidence from an accident investigation being used in criminal proceedings. Countries that are members of ICAO agree to this and their regulatory authorities incorporate it into their system.
The issue is NOT whether or not pilots can or cannot be prosecuted for negligence, it is the question of what evidence can be used in court to prove this. CVR's cannot be used to prove innocence either.
Illegal phone tapping constitutes and produces similar issues, there are a number of other examples.
Removing these protections or ignoring them reduces the ability of investigators to get at the causes of accidents and thus prevent the next one.