I think you just answered your own question. You respond to the person making the accusation by saying, "I think we mean two different things by communism and Marxism. You might mean Stalinism, but what I mean is X, and X is what I'm fighting for politically." The human nature is so tired and lame that I am beginning to suspect that there may be a human gene with the argument encoded into it. But no, seriously, the response to that is to emphasize that capitalism heightens people's competitiveness and self-interestedness to the point of making selfishness a kind of virtue. Everybody naturally has an instinct for self-preservation. Desiring to see people remain homeless when there are millions of empty and unowned houses -- that's capitalist selfishess.
You hit the nail on the head there. Big thank you for helping me out! I'm sick of the 'human nature' argument too, it seems that it's the only thing that they can possibly muster up, so they continue to push it and push it until they hear what they want to hear, which of course, wont happen because they are the selfish ones.
My quest for equality began many years ago. ~Amon
