Slavoj Zizek discusses the "Beautiful Soul" tendencies of middle-class liberals, whose preoccupation is winning moral victories rather than real ones. This leads directly to sectarianism, to lifestylism, to politics which isn't really politics, it's just gesturing to make yourself feel warm and fuzzy. Contrast that to the tradition voiced by New Model Army in "The Charge" - no-one needs morality when there isn't enough to eat. This latter tradition is the one that Chaos Marxism stands with.
The fact is, to win anything in the World-As-Is, you have to compromise, make deals with the Prince of This World (the Great Deceiver, the System, etc). So anyone who wins by necessity will be morally impure. The only question in the end is was it worth it to bring something new into the world. Was it worth wiping out the entire Banu Qurayzah to make sure the Muslim community would be safe, or backpedalling on the equality of men and women to ensure the unity of that community? Were all the horrors of the Russian Civil War justified to prove that it was at least possible that every cook could govern? Is Hugo Chávez justified in congratulating the awful troll in Tehran on his most probably fraudulent election victory, to keep diplomatic and economic ties with Iran strong? Did
Perhaps there are no answers to any of the above questions. The fact is, to do anything in this world means going up against all the forces which want us to remain quiet. It means doing bad things, it means sinning. A sin is always forgiveable, never acceptable... sometimes excusable.