Capitalism is the most moral economic system yet devised. It lets people become rich to the extent that they provide a service for others. That’s not to say that capitalism is perfect, simply that every alternative system leaves people poorer and less free.That nails it for me. I'm not a Gordon Gecko type. I'm not a big earner. I'm not even a particular fan of capitalism and don't see it as something to be achieved. It's just a by product of freedom, no more or less than the system you're going to end up with if you recognise that people are naturally free to earn and own to the best of their ability. If there was a communist or socialist economy that was big on protecting individual liberties and property rights I'd happily bang the drum for it, but the reality is, as Dan Hannan says, that the alternatives to capitalism invariably means more poverty and less freedom, albeit incrementally in some cases. I honestly don't care too strongly about capitalism itself but I value freedom as highly as oxygen.
I'd happily ditch capitalism in favour of anything else that came along if it was better at providing prosperity and defending liberty, though since I think that capitalism is just a name to hang on what you end up with when people are free I'm not convinced that such a thing is even possible.
No, it's not perfect. It's just the best there is.