Dry vs. canned food IS a factor in urinary blockage and crystal formation. Reduced or insufficient fluid intake is a contributing factor in many urinary and bladder conditions, for both people and pets. "The solution to pollution is dilution" and minerals as well as bacteria are condensed and not moved out of the body as quickly when moisture levels are low. In addition, this concentration often leads to changes in pH which are favorable to crystal formation. Cats are not natural water drinkers as in nature they get the majority of their fluids from the bodies of their prey. When they are fed a dry kibble diet, their daily water intake is far below that of a cat fed a canned or raw diet. Other factors can influence crystal formation, including food content, but reduced moisuture intake is the biggest risk factor.

Raw diets are far from "a complete fad" and are ideal nutrition for pets when the owner ensures the recipes they feed are balanced. It is absolutely not true that "licensed veterinarians absolutely do not recommend feeding raw diets to dogs or cats" and in fact, many do and will specifically refer you to veterinary nutritionists for custom formulated recipes, especially if your animal has a special need or disease. Most vets know next to nothing about nutrition themselves as it is not something covered in depth in the course of regular veterinary school. The cat's organs and tissues benefit from higher quality protein and the absence of unnecessary and inflammatory grains. Taurine need not always be supplemented if additional organs and hearts are included in the recipe, but you're right, it is essential cats receive it in their diets. The calcium:phosphorous ratio is also of the utmost importance. Raw feeding is not by any means hard, and it is cheaper to feed raw, you just have to put in a little prep work or use a professionally formulated recipe.

As many others have said, DE is commonly used for parasites both internally and externally. Avoid letting your pet breathe in the dust and get food grade DE.