Well to be fair the OP doesn't use the phrase "evil rich guy". But anyway, taking arguments to their absurd extreme is a time-honored way of testing the validity of your premises, and that is what it sounds like this guy is doing.
I think one major thing the communist friend is missing here is the gains from trade. It would be against the self-interest of the evil rich guy to kick everyone off the earth. The argument is equivalent to, say, a dictator, kicking everyone out of his country-- it just doesn't make sense.
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