That is a good question. I look for what works in a given situation over a tradition. It is more important for humans to take their homeopathics away from other things with flavor because the brain might look at that stimulus instead of the information in the homeopathic preparation. Animals generally are not consuming very spicy foods, mint, smoking, or consuming caffeine or alcoholic beverages in the course of their meals, so in reality the product usually works quite well even when added to their food. If changes aren't seen, one could syringe the homeopathic preparation directly into the pet's mouth either diluted with a small amount of purified water or undiluted. It can also be added to a non-metal water bowl filled with purified water. Be sure not to use a metallic spoon to measure.
Because there are so many homeopathic substances available in the world the general rule tries to avoid interference just in case the remedy you are using is very sensitive to any of the above antidotes. I like to make it as simple for the owner so they will comply. A product that is never used doesn't help the patient either.