In GP's example, capitalism has made food production cheaper and less labor intensive so that more people can get it, relatively.
But for me, your example is capitalism in the sense that people do it of their own free will. They give up their time and resources to help others without coercion or compulsion. Capitalism is freedom to me, and a natural state that exists outside of the state where people can interact freely with one another. What they do with it is another question entirely.
Others, however, equate capitalism with greed and evil though.
Human nature to help one another doesn't exist because of capitalism though. In tight-knit Amish communities for example, communities come together and help each other out. Or under feudalism, for example, I'm sure people still helped out other people with no coercion from time to time.