is that doing so will only release heat into the refrigerator and warm up everything else. thus, not only will your hot food not cool down very quickly, but anything else, such as your milk, will become warmer. thus, there is no advantage to placing overly warm foods in the refrigerator and you are only going to cause other foods to spoil faster.
some folks say this depends on the type of food, as well. for example, while it is fine to place leftover meat in the refrigerator right away, you should wait for a large pot of stew or other such food to cool down to room temperature, first.
while it 