The definition of 'purpose' that I have internalized is 'a subjective claim about what a system does and why it was built/evolved to function in that way.' But I think the concept of purpose being used here is 'the function the system performs.' Capitalism is so horrible because it reduces the 'purpose' to all human life down to 'that which makes profit'; a car isn't 'for moving' it is 'for making profit', a hospital isn't 'for healing the sick' it's 'for making profit.'