Could it just be that whistleblowing is intensely stressful and difficult (reporters, lawyers, harassment from former coworkers and company fanboys, difficulty finding new employment, etc.) I imagine all of that makes whistleblowers far more susceptible to disease and mental issues.
We need stronger whistleblower protection laws. Not just in case companies put out a hit, but also to help the whistleblowers endure and recover from doing the right thing…