The above passages are from an article published on Common Dreams called "Is Obama a Socialist? Reflection on the Degradation of Politics and the Ecosystem" by Robert Jensen. Definitely worth reading the whole thing.
As with any complex political idea, socialism means different things to different people. But there are core concepts in socialist politics that are easy to identify, including (1) worker control over the nature and conditions of their work; (2) collective ownership of the major capital assets of the society, the means of production; and (3) an egalitarian distribution of the wealth of a society.
Obama has never argued for such principles, and in fact consistently argues against them, as do virtually all politicians who are visible in mainstream U.S. politics. This is hardly surprising, given the degree to which our society is dominated by corporations, the primary institution through which capitalism operates.
In short: Obama and some Democrats have argued for a slight expansion of the social safety net, which is generally a good thing in a society with such dramatic wealth inequality and such a depraved disregard for vulnerable people. But that's not socialism.
UPDATE: I've decided to give you one more excerpt from the article mentioned above:
You know, that was obvious to me decades ago. But I think capitalism is like some diabolical religion to many people in this country. Like the Heaven's Gate cult, they would rather commit group suicide (the group this time meaning the entire planet) than question this "faith".
But capitalism is not only inhuman and anti-democratic; it's also unsustainable, and if we don't come to terms with that one, not much else matters. Capitalism is an economic system based on the concept of unlimited growth, yet we live on a finite planet. Capitalism is, quite literally, crazy.