"Lefty" is just a term to identify the "left" party in partisan politics. I don't see it as derogatory, nor would I see "righty" as derogatory.
Adding "Nut" as a suffix would make it a problem.
Free speech ends when the board starts to disintegrate. Just as we need a benevolent dictator in the country to flip us back off our heads, we need on this board.