[lil fu fu girl]

In acknowledgment to your first statement, yes chicken meal does contain more protein then the chicken listed as an ingredient by itself, as you simply stated due to the fact of water content, and yes, meal is very easy to digest, especially for puppies.
In answer to the question about the number 5; most kibbles at present not only add in gluten,but also starch , flour, syrup etc. of corn and various other carbohydrates. Usually you will see the main source of meat protein as the number one ingredient, and then in some kibbles, an assortment of corn or grains and their by-products. So in essence, even though the meat is labeled as the first and primary ingredient, its weight is far less than the combined next 4, when they are all by-products of corn or grains: if that makes sense to you. In nutritionist speak, "The first five" ingredients, are ones of the most nutrient dense significance, or they should be.
As for corn, it is not a complete protein, however if combined with legumes , such as beans, the body can then synthesize the proteins to form a complete protein. However, as stated , this taxes not only the liver but also the kidneys due to the waste materials that are generated in the bodies processing of it.
As for human grade meal, I should have stated " Human grade" for the meat used in the meal. My mistake. Most meals processed for our pups are not from human grade meat products, as we all know, they are from a whole different realm in the processing plant.
HSUS states:
"Currently, downed animals, as well as other condemned meat, can be used in pet foods. These meats, known as the 4-D—dead, dying, diseased or down—meats, are sent to rendering facilities, along with other offal (animal products considered unfit for human consumption) from factory farms. They are then boiled, melted, or otherwise processed to become tallow, meal, or other ingredients to be used in edible and inedible products, including pet foods."
As for toxins being present after our food has been cooked, sterilized, processed etc, allow me just to say ....omg..... YES!
Staphylococcus bacteria produce toxins (or poisons). While the bacteria can be killed at 120 degrees, its toxins are Heat Resistant, and remain in the food.
Clostridium perfringens, more commonly known as botulism, can survive hours of processing, and not only that, but the cooking drives off oxygen, kills competitive organisms and heat-shocks the spores, all of which promote germination.
vCreutzfeldt-Jacob disease , does not go away with any amount of processing, that is why the cattle are burned. And in consideration that the "downed" meat is allowed in our pets "meal" this could affect them as well. Not to mention Scrapie found in sheep, or the new Wasting Disease transmitted through deer meat. All of these are not effected by heat processing.
AGE's ; Advanced Glycation End Products are formed when meat is sterilized and pasteurized, have now been linked to diabetes, kidney disease, Alzheimer's etc.
These are to name but only a few, there are many, many more.
Having been in academia for a Nutritional Science degree, I realize that you are absolutely correct. There are some who have but a glint of nutritional designs, and yet, they approach the field as an expert. I am by far, no expert. However, I do consider myself educated in the field, or , at least I try to be
Hope this clarifies my opinions.......