You would have to be crazy not to be afraid of the "what-ifs". People who go up against powerful entities such as Boeing and the US government with credible evidence of serious crimes have a history of ending up dead, tortured, falsely imprisoned, or in the best case, living the rest of their lives in hiding.
Ask Julian Assange or Edward Snowden, to name a couple.
It doesn't have to be that bad before people think it's too much. People get blackballed and never can get a proper job in the profession they're proficient in. That's often enough. Who in their 40s or 50s wants to start anew?