> The nature of people is to be greedy and keep what they "want" or think they "need", not just what they actually need. Socialism asks (and eventually commands) people to give up things they wouldn't otherwise give up for the good of others

No, it doesn't.

First of all, socialism did not start off as an egalitarian ideology or idea. Saint Simon, who coined the term, was originally promoting a technocratic meritocracy, which would still have substantial hierarchy. The key was to pay people and give people power according to the value they created, rather than according to ownership of property or titles. Because this would have a de facto effect of massive redistribution of wealth, redistribution have come to be seen as a major defining aspect of socialist ideologies, often with welfare as an alternative mechanism of providing that redistribution, and this has coloured many later socialist ideologies.

Over the following decades, the term came to encompass ideologies all across the political spectrum, ranging from those who saw socialism in the context of religion or feudalism: A moral duty to take care of the weak or those whom you rule. To those who wanted an ideal, entirely egalitarian society built from scratch - the utopian socialists.

In between we find people like Marx, who devoted a chapter of the Communist Manifesto to denounce a long laundry list of the other forms of socialism, and who extensively criticised exactly the claim you make.

A key aspect of Marxism is the focus on the class struggle, and this has infused most later socialist ideologies, from the 1840's onwards. The key point Marx made was exactly opposite of what you claim:

The problem for socialists is to educate the working classes so that they understand their own self interest, and stand up for their own interests rather than accept and believe that the ruling class has their best interests at heart. That means for the working class to stand up and make their demands heard, and refuse to accept dictates from a non-working class minority.

The fantasy that socialism is about people "giving up things for the good of others" is an idea bandied about primarily by people who look at their own wealth or the wealth they aspire to (consider Steinbeck: “Socialism never took root in America because the poor see themselves not as an exploited proletariat but as temporarily embarrassed millionaires.”) and sees that they would need to give things up in a socialist society (or they believe they eventually would, or that it would curtail their chance to get rich).

On the contrary: Marxist socialism which is usually what people talk about when they throw this idea about, is about the enlightened self interest of the working classes. About demanding a greater share. And if necessary about taking it, gun in hand, from those who Marx insist will use violence to prevent giving up their privilege.

The very insistence in Marxism on revolutions as the mechanism of social change is down to this fundamental belief in the selfish nature of man: Marx was very insistent that no privileged class will willingly give up its privilege, and so while it is useful for a class to organize and attempt to change things peacefully, ultimately it almost certainly will come down to a violent overthrow of the old regime.

He spent a great deal of time insulting dreamers who fantasized about building socialist communes and gradually and peacefully changing the world, or who thought socialism could realistically be achieved through elections (though he was not against attempts he expected any winning socialist party to face the use violence to prevent them from following through their programs - a prediction that has come true more than once).

If anything, then, Marxism not only assumes that people are selfish, but is predicated on the assumption that people are ultimately more selfish than their behaviour in capitalist society lets on: If only the working class is sufficiently taught about the realities of class struggle, Marx believed they would eventually rise up against it to demand more for themselves.

Marx further claims that the fundamental criteria for a socialist revolution to be successful, is that society both reaches a state where the majority of the population has become sufficiently poor as capitalism develops that redistribution will be to their advantage, and society as a whole has gotten so rich that such a redistribution will not only be a material advantage for the majority, but sufficient to lift them all out of poverty and provide sufficient wealth that there is little incentive to circumvent societal rules to obtain more.

To quote Marx from "The German Ideology" (1845):

'This “alienation” (to use a term which will be comprehensible to the philosophers) can, of course, only be abolished given two practical premises. For it to become an “intolerable” power, i.e. a power against which men make a revolution, it must necessarily have rendered the great mass of humanity “propertyless,” and produced, at the same time, the contradiction of an existing world of wealth and culture, both of which conditions presuppose a great increase in productive power, a high degree of its development. And, on the other hand, this development of productive forces (which itself implies the actual empirical existence of men in their world-historical, instead of local, being) is an absolutely necessary practical premise because without it want is merely made general, and with destitution the struggle for necessities and all the old filthy business would necessarily be reproduced; '

This was in fact a key aspect of the schism between the Bolcheviks and the rest of the Russian communists. The Bolcheviks, amongst other differences, rejected this idea in favour of a doctrine published by Lenin in 1893 that outlined how he believed that the Russian landless peasants would come to the defence of a socialist revolution. They did not, and the eventual outcome was what Marx had predicted: "all the old filthy business would necessarily be reproduced", in the form of the Soviet regime that no sooner had they torn down the last vestiges of the old, they rebuilt the same types of power structures and class rule in their own image, and started grasping for the same privileges they had fought.

> capitalism is inherently based upon freedom of the individual while socialism is inherently based upon lack of freedom for the individual.

No. Capitalism is inherently based upon the free exchange of property rights. While socialism is inherently based on reward following merit rather than property ownership. The two are not opposites. Nor are they even similar things.

Socialism is not an economic system, but a set of properties shared by vastly different ideologies across the political spectrum. If you when you say "socialism" speak of Stalinism or Maoism, or a similar feudal or state capitalist ideology with socialist features, you are right. If you when you say "socialism" speak of Marxism you would be wrong, as would you for dozens of other socialist ideologies.

A major part of the disconnect is that US style "libertarians" tend to define property as a natural right, and then evaluate freedom in terms of whether or not already partitioned property rights are infringed on, and expect either government protection of those "rights" or the right to restrict others freedoms to keep them off the land, while most far left socialist ideologies starts with the individual and asks what restricts the individuals actions. Thus we arrive at statements like Proudhons "property is theft": Resources are limited, and thus any act that assigns property rights take rights away from others, and limits their freedoms.

You can not have maximal freedom without substantially curtailing property rights. You can also not have maximal freedom without some rights to property, though whether or not those rights include actual ownership in the capitalist sense is orthogonal to the issue of maximising freedom.

Most nations implicitly acknowledge parts of this: Many property rights are protected from private ownership and/or much property is held in public trust in the interest of guaranteeing people the freedom to make use of the land. E.g. in my native Norway, anyone has right of way through forests and any other undeveloped areas, even if someone has private ownership rights to it. You can walk through it. You can camp. And the owner can do very little about that. This is because society explicitly acknowledge that the moment you let someone throw others off the land, that person has had their freedoms restricted. At the same time, the law recognizes trespass that infringes on the private sphere: Entering a garden surrounding a house is entirely different. While restricting access is reducing other peoples rights, allowing unfettered access is a much stronger and more direct infringement of the rights of those who live there.

Getting a tradeoff that maximizes freedom is hard, but it most certainly does not involve unfettered rights to private property.

You know what tends to freak guys like you off the most? Despite the above, in discussions chances are you'd find more common ground with me than either of us would find with a social democrat or mainstream European "socialist", because they tend to be "big government" socialists, while as a Marxist I see the end goal as the wholesale abolition of the state.

Back in the day, I had libertarians cry in debates because they hated it when I agreed more with them than with the people they tried to lump me with...