pitchfork = the big iron fork that farmers use to move hay
It's also the tool of the devil. When people argue by throwing verbal abuse at their opponents, we call it "pitchforking". This is often the way of the extreme left of the political spectrum aka unions; socialists.
Centre-right is the trend of democratic politics in modern times.
As for the word "to pit"...
The contest pits one person against another.
to pit = to put into heavy contention for