*sigh* "Form of government" meaning an "idea of government" which includes the lack of one.

Everyone does not have equal chances of for example getting education in a capitalism. In a capitalism the only thing that matters is one's economical wealth and everyone is not born with the exact same amount of money. The rich have bigger chances of succeeding in life from the start. They are the ones who will own the large corporations, which grants them the right to create the rules and to oppress the ones with less power/the ones who are born poor. If you are born in a poor family, it will take a lot of luck to get a highly paid job, while a person born wealthy can buy himself an education that guarantees a good job. In a socialism everyone will receive the same education sponsored by tax payer's money. This will, unlike in a capitalism, give everyone the freedom to educate oneself to whatever one may desire and the economical wealth of a person is totally irrelevant. Therefore a socialism is both more equal and free than a capitalism.
That makes one gross assumption: that "success" is measured in monetary means. I find that distasteful.
In capitalism, you have choice(which is freedom). In communism, you don't(which is equality).