Seriously think about it. What has True Leftism brought us?
Liberalism/progressivism brought us the 40 hour work week, Social Security, Medicare/Medicaid and the universal healthcare of other countries.
True Leftism has brought us the gulags, the Cultural Revolution, the Great Leap Forward and the Khmer Rouge.
Yeah tough choice which ideology I'm going with...
No, it was leftist/labor agitation which pushed those and forced the dithering "progressive" governments to act on them. The domestic policy achievements of Roosevelt and Johnson did not originate from the top down.
I could also tell you how divided and politically diverse the far-left is and why it's inappropriate to place, say, Stalinists with syndicalists, but you wouldn't understand that.