I've read the sentence about anarchists ten times and I have no idea WTF he is on about. Btw the nerd's name is Peter Hudis.
Edit: FFS Tankies and anarchists stop shitting on each other here. Take your struggle session elsewhere. You're both my comrades.
The failure of anarchism was with the end of the "direct actionist" wing of the labor movement in the 1950s. Anarchism offered one of the strongest socialist alternatives this country has ever seen and they were punished for it. They were rewarded with pinkerton gunfire, state assassination, imprisonment, AFL raids, and more.
There were internal issues, sure, like the split between the anarchist and socialist wings of the union, or the failure to unite immigrant workers with black workers, but they still probably wouldn't have withstood the outside pressures.