From Free Association (www.sheldonrichman.com):
Why do economists, even those who favor the free market, call what the market process does "rationing." When you choose, because of the price, to buy four pounds of hamburger rather than eight, that is not rationing. Rationing is when an authority says you can only buy four. It indicates a conscious process of allocation of other people's property. The market is not a conscious process. Rather it's a bunch of people engaging in conscious exchanges involving their own property to improve their situations. That's very different.
I think it does the case for the market harm to call what it does rationing. The other side can say: "I agree. But the market is a cold, impersonal rationer. We need a kinder, gentler rationer: the State."
I don't think we should want those to be the terms of the debate.
Later thought: When I enter a store and spend $50 rather than all I have, would we say I rationed my money to the store owner? Who would talk like that?