I agree that a predominately vegetarian diet is the healthiest, but not an exclusive ones. While some, but not all, of the longest lived peoples on earth eat predominately vegetarian diets, NONE of the longest lived peoples eat exclusively vegetarian diets.
In no way can I agree with the idea that man has evolved or adapted to become exclusive vegetarians . That does not at all match the known nutrtional needs for optimum health and neither is it logical to believe that man has made an evolutionary leap from hundreds of thousands of years of being omnivores and still having the teeth of an omnivore to suddenly become vegetarians without the very large majority of humans eating an almost exclusive vegetarian diet for a great many generations. Currenly, about 2-3% of the U.S. population are strict vegetarians.
Quite obviously, we like our meat. The key is eating healthy meat in reasonable healthy portions.