Actually, it's not. It should make you question this idea that is a part of low-carb and Paleo diet thinking (although it's not really "thinking" if you don't ask these questions, is it?).
The picture is taken from the book "Hungry Planet", which is a coffee table book about the typical family diets in countries around the world.
I don't have any problem with the idea of reducing carbohydrates in your diet, but as always the wonks go over the top in an attempt to be as pure as an Islamist suicide bomber in their belief.