The is left
There is right
and then there is "loony-bin" crazy.
"Loony-bin" is a bi-partisan condition.
Of late the Left does seem to have a few more high profile nut-jobs than the right, but over the long haul this is a cyclical matter.
I am sure things will swing back to forth like it always does.
Back in the late 1990s, the "looney-bin" pendulum had swung far too the right. Then with the 2000 election, 9/11 attacks and the war of Iraq, the pendulum has radically swung back in the other direction to where I'm now pretty sure the "looney-bin" pendulum is very far on the left, probably much further than it was with the right in the late-90s.