The real lefty nemesis are all the feds who pretend to be leftists until they see any leftist doing any real leftism and then they immediately shove the boot all the way down their gullet
That's why even if I have my own personal views, I identify primarily as an anti-sectarian Leftist. Whether Marxism, Anarchism, or some other flavor of Leftism begins to truly lead the movement, it will be more important to push the movement forward than to spend effort on infighting.
Only a mass worker movement can get any real change.
Leftists biggest nemesis are liberals, and they think they have 94% of the same views but they do not.
[ In fake Scottish accent ] They're natural enemies. Like fascists and leftists! Or neoliberals and leftists! Or moderates and leftists! Or leftists and leftists! Damn leftists! They ruined leftism!
Next at 5: Watch tankies, democratic socialists, and anarchists engage in a full blown shit flinging contest!
We take the whole "You have my sword. And my axe." trope a little too literally.