That picture in no way depicts a true paleo diet and while paleo excludes things its things that are crap you can still induldge in many things that are commonly eaten just with cleaner versions.
It is not low calorie at all as the grassfeds meats are high in good fats as well as addition of extra fats and starches like sweet potatoes. Fiber can be found in extremely higher amounts in veggies like green beans than the processed stuff like cereal, pasta and crappy bread that we cut out.
On the last note crossfitters are not nuts anymore (and in fact less) than people who jump on an spin bike for an hour every morning. They are people worried about there health and doing something about it.
With Paleo and Crossfit I lost over 150lbs, got off blood pressure medication, eliminated my risk for diabetes and returned my cholesterol to normal levels. I have perfect perfect bloodwork now. Oh and now longer have a vitamin D deficiency which is saying a lot when I live in the PacNW
Do your research next time before you post something that is all conjecture.