Capitalism = you earned what you get
Earn is a very loaded word, I'd be cautious about using it. For example did Bill Gates earn 50billion dollars or whatever he has? Did he work that much harder or have that many more ingenious ideas to deserve such astronomical wealth? He earned it, in the sense that he made that much money legally under the current laws of the country/world, but earn implies some sense of justice. Does someone who inherited their fathers wealth earn it? To claim that capitalism means you earned what you get is a little simplistic.
I went into detail about capitalism and the environment a few pages back. Read it.
Anyway I think the point neutrino is trying to make is that even if you disagree with implementing a communist or marxist society as a whole, you shouldn't just dismiss all the teachings of that philosophy. For example Marx's critique/exposition of capitalism is still relevant today, and really hasn't been bettered, only refined. If you actually engage with the philosophy you'll probably find you have much to learn from it.
Has a utopian society existed in the past: NO, otherwise it'd probably still be around, however there are plenty of examples of societies or tribes that have shown sucessful implementation of communist style ways of life, that suggest that communism isn't fundamentally against human nature.
What follows is a brief exposition of some aspects of Marxism, not necessarily part of the debate, just posted because I started typing something, forgot what it was about, and ended up rambling.
To Marx who believed in a history of dialectics, that is that humanity has moved along obvious paths, and when the motivating factors behind these paths can be discerned we can predict the future to some extent. This idea was taken from Hegel. However Hegel held that history was the product of the evolution of a spirit (towards truth or some such I think...) while for Marx history was determined by class struggles and the methods of economic organisation.
To him tribal communism was distinctly different from his vision of communism.
Tribal communism sufficed to sustain the needs of the primitive societies for most of humanities history, but didn't exactly lead to progress, as when the surplus resources were divided out the little that went to everybody did little to progress society.
Tribal communism was suceeded by Feudalism, as that ensured the best way for society to progress. As there weren't enough resources for everyone to be well educated, feudalism ensured that a few were, and then given positions of power, or importance such as trades.
After the industrial revolution feudalism was replaced by capitalism, as feudalism could no longer respond to the changing nature of the market.
Marx believed that the next step in societies progress would be towards communism, as after the market had generated sufficient resources for people to be educated etc. it would no longer be the best way to run society, as it would fail to respond to the needs of society, or advance it, in the same way that tribal communism and feudalism had become outdated.
Of course the last step was the most controversial, and Marx seemed sure that the move to communism would occur in a very brief period of time, once the workers realised that the means of production no longer served the ends of society. The fact that these predictions have failed to materialise many years after they were made has led to embarassment for some marxists, and also a dismissal of Marxism by some.
Other marxists have saught to advance theories as to why the working classes still haven't risen up, including people like gramsci who first advanced the theory of hegemony, which has had a huge influence on cultural analysis by different groups of people, such as feminists, colonised people etc. Traditionally capitalist control is maintained through violence and economics (eg. police enforcing capitalist laws, creating a state whereby it's extermely difficult to live outside capitalism and not be in poverty).
Gramsci theorised that as well as this, there's also hegemonic control, that is the control of culture and thought.
Later Marxists have expanded on this theory of cultural control, and been influenced also by post stucturalist criticisms. In my opinion the most persuasive one is Louis Althusser, who developed a comprehensive if sometimes depressing theory of ideology.
While earlier Marxists held that if we destroy the hegemony we can percieve truth (and with it the nature of class relations) Althusser claims that all action is done within a given ideology, and when the hegemony of the ruling class is displaced, it won't lead to truth, but rather another ideology.
Criticisms of popular culture have been heavily influenced by later marxist thinkers.