If I had to guess it’s because these companies are straddling the line between socially aware company (to attract this conscientious minded employee) and the realities of doing business (core competencies and flexibility when things go south). Given the above a small percentage of employees feel an obligation to look after the subcontracted workers, etc. and want to bring it up as an issue in the next election cycle.

I doubt you’ll see this attitude at GM (despite unions) or Archer Daniels Midland, etc., because they don’t try to play both sides as much.