There is a list of FDA-acceptable propellants. They are part of the contents, but they are not part of the product which is consumed. Therefore, they don't need to be specified.
Moreover, manufacturers are free to arbitrarily change their propellant formula based on the cost and availability of ingredients -- without having to re-label.
Finally, if you put the propellant ingredients in the ingredient statement, you'd be having women like this one having a cow in the middle of the supermarket aisle.
Most people are perfectly satisfied with this arrangement, trusting the FDA and the food manufacturers that they're not interested in killing off their customers.
Unfortunately, you're not. But you're free to complain about it. The Center for Science and the Public Interest (which has little to do with science and nothing to do with the public interest) would be happy to receive your donation -- as their primary business is fund-raising.
Okay, let’s take one example from the whole story, which might not be the best example or best idea, and kill the whole point of listing ingredients because of that. For me the bigger issue are the GM foods. If the propellents can be changed at will due to availabiity, cost, etc. then fine, explain that to me and move on. No need to be an ass while doing so. How about listing the propellents like they do oils on the list of ingredients which are commonly listed similar to “cottonseed and/or sunflower oil” because they use them interchangably. Aren’t oils also arbitrarily changed based on cost and availability? Why is this any different? Because the propellent isn’t directly consumed? Then why is it listed in the ingredients at all?
Just because you’re happy to go along with whatever the government tells you is fine doesn’t mean that everyone else should be. I’m still not seeing what the big deal of listing all ingredients is. But you’re free to complain about me wanting to know them.