I am a capitalist, because capitalism is what can give 6,000,000 people a decent life. I employ as evidence for it's power to do that the only example I have, the 100 years following 1776. That 100 years gave the world extraordinary peace and theretofore unimaginable prosperity.
It is during that 100 years that capitalism in substantial part existed in the world.
Capitalism is a name given to a condition in which private ownership and free trade exist. Capitalism, with its inherent absence of arbitrary coercive forces, yields a condition that is fit for human habitation.
You "liberals"- on the other hand have thousands of years to draw from for examples that prove the effectiveness of your statist system.
You can start with the Russian experiment. Even after Stalin they tried for 50 years to make it work. Gorbachev is probably as compassionate a leader as the world has ever seen. You have here book ends. Neither the ruthless nor the compassionate have ever made your statism work to the benefit of anyone except the few elite.
Statism is the name given to a condition in which "A"- gets together with "B"- to decide what "C"- should give to "X"-.