Just as an anecdote, I used to moderate one of the more popular political subreddits. It was a difficult task and burnout on the team was common. I can say that the mod team was not just shills for a particular party (unless they were undercover even to me). The entire mod team, even to this day, is there for altruistic reasons - we felt we were doing a service to our fellow Americans by fostering healthy political discussion.
I moderated that sub through election season and then stepped down in January. At the end of the day the death threats and constant insults aren't what drove me away, but the organizational chaos. No one could figure out how to lead that team, and leaning on practiced organizational structures was apparently too hard for a group of redditors.