Anarchism isn't the only leftist philosophy, it's just the most utopian.

That's not really true, you can get to anarchy from the left or the right. In fact, anarcho-capitalism is pretty much what American libertarians have been pushing for decades. There is an anarcho-communism, which involves abolishing all hierarchies and monetary systems are relying entirely on mutual aid, but I think most of the, "far-left," in America is just marxist, usually socialist but sometimes communist.

I think it's similar to communism in the sense that they fantasize about perfect citizens who would always think about the group before themselves without any other incitation (such as having to earn money to live).