I suspect the answer to the second question is "both, plus the fear that unionization might spread and show the proles that they actually have the power to turn

I suspect the answer to the second question is "both, plus the fear that unionization might spread and show the proles that they actually have the power to turn things back in their favor, and end the gravy train that has let the already-wealthy take nearly all the increases in productivity for 50 years to line their pockets."