Well if he said that, then Prater would be unfit to act in his own profession.
A professional pilot (and competant captain) would let no issue not directly related to the flight interfere with or negatively impact the conduct of that flight or the atmosphere in the cockpit.
I'm not a "Republican", but that statement clearly indicates he'd let outside personal feelings he may not agree with having NOTHING to do with the flight affect how he'd treat a subbordinate crewmember. Politics, religeon or the price of milk, it does not matter.
If true, John Prater should not only be recalled from his ALPA position, he should resign from the industry as he is a hazard to safety and a disgrace to the airline pilot profession.