@matigo Yes, I would agree that the majority of the population consumes animal-based products on a regular basis. I also have read medical and nutritionist opinions that a well-thought out plant-based diet is generally better for health and longevity than the corresponding omnivore diet that includes animal-based products.
When you say "writing for exceptions means that you write for nobody," I guess I sort of get where you're coming from (maybe you are talking about identifying with a specific audience?), but in the case that @phoneboy mentioned, we are talking about a government-penned website that advocates whole foods including meat and animal-based products for better health. While eating whole, unprocessed foods seems to be better for your health without question (avoiding artificial additives, for example), it seems to me that there is some medical and nutritional basis for questioning the validity of the assumption that animal-based products have to be part of a "balanced diet" for good health. The fact that the U.S. government has published such a document makes it doubly so.
// @phoneboy