In the United States, there were cultists associated with liberal causes about 50 years ago--as anti Viet Nam invasion efforts failed--leading from demonstrations to criminal behavior--most extreme being the Manson cult. In time that led to a drop out culture that had given up on government.
From that anti war perspective, both Demos and Repos swung to the right--and some kept right on swinging into the Teapers, and Truthers. The only remaining liberal issue, social justice, was sufficiently supported by the Demos to draw some--but not with the enthusiasm as before. The fire from the left is gone.
That's why this thread doesn't really accept your "bookends" analysis. The left cultist leftovers are in senior citizen centers.