Let me see if I can make this even simpler:
1. There is more than one meaning of the word rationing. Economics is a young discipline, and hasn't had the opportunity to nail all its terms down as perfectly as philosophy has. There is a fairly rare technical usage, which refers to any allocation of a scarce good: i.e. "price rationing versus fiat rationing". Then there is the common usage of the term, which refers to a fiat system in which the government uses fiat in order to abrogate the price system and impose a different distribution of the aforementioned scarce goods.
2. The former is a fact. The latter is a mistake.
3. It is no more technically incorrect to use both the common usage and the technical usage in discussing an issue than it would be to use "cost" in both the economist's sense--as any price, non-monetary or monetary, attached to an action--and in the common usage, as "price".
4. My problem with the latter is that abrogating the price system generally results in a distribution and supply of goods that does not enhance the general welfare, or even, in the long run, the welfare of the people it is supposed to be helping. (See, United Soviet Socialist Republics, economic history of). There is substantial reason to believe that rationing in World War II led to sub-optimal material outcomes, whatever its moral or spiritual benefits.
5. That said, Mr. Holbo is mistaken about the common usage. Rationing does not have to control 100% of a relevant good in order to constitute rationing, and indeed, no government ever succeeded in doing so (or for that matter, tried particularly hard). For example, during World War II, people who ate in restaurants could get around some rationing requirements in the US, and I believe also in Britain. Taxicabs got preferred access to gasoline. Both allowed the wealthy to "opt out" of the system. Yet I hope we can both agree that rationing during World War II was in the common sense, rationing.