From The Barefoot Bum, an argument that makes sense to me, amongst a lot of arguments that don’t:
I’m a revolutionary communist because my conscience is deeply shocked by the crimes perpetrated by our existing political system. I’m shocked by the suffering and oppression this system entails, proven by both empirical historical evidence and theoretical analysis. I’m no longer willing to work within a system that gives me only the choices between bad and worse. I’m no longer willing to remain silent about some suffering only to avoid even worse suffering.
Just asking for a little less oppression isn’t enough for me any more. I may be mistaken, but I believe that a radical transformation of society — and only a radical transformation — can end all oppression.
To bear witness to the way things stay the same is often depressing. To continue to believe that the transformation is possible, that it is worth devoting oneself to, is evidence of profound and radical optimism and faith in humanity, a faith to which few “religions” aspire.