As a student of history and economics, I've long believed that capitalism is a much more moral system of human exchange than socialism or communism. Capitalism causes mutually beneficial relations between people. In the process it honors individuals, their talents, their ambitions, their choices and their values. To say that a system based on self-interests and the profit motive is more moral than one where government controls the means of production (through tight regulation or ownership) and redistributes private wealth is counter-intuitive to some people. But, it's true, though hard to effectively articulate.
The best explanation I've seen on this is a piece titled "An Audacious Promise: The Moral Case for Capitalism" by James R. Otteson. To set up his case, he dismantles the argument by President Obama that capitalism has failed. Don't be put off by what seems like a political statement because it's not really an article about politics. Otteson's real purpose is to make that case that capitalism as practiced over the past 200 years or so is a bright spot in an otherwise brutish 100,000 years existence of our species.