Perhaps that is true for a vegan diet where you only eat standard American food, but a whole foods plant-based diet has been shown time after time to lower risks for all sorts of diseases, from heart disease to cancer to parkingsons and MS.

Iron and calcium are in plants, D is in fact added to milk, and can be added to a plant based diet via a pill as well if you don't synthesize enough. You are an animal; your body creates enough creatine (creatine production is in fact downregulated when you consume meat). B12 can also be added via a pill, and it is already added to many foods like cereal.

When you look deeper into the facts, you will see that the Standard American Diet faces far more deficiencies, the most obvious being fiber.