Vegetarian Neanderthals and what that implies

Per NPR studies of the dental calculus (hardened plaque, tartar) from three Neanderthal specimens showed that the individual from a cave in Spy, Belgium was largely carnivorous; while two individuals from El Sidrón cave in Spain were vegetarian.

Laura Weyrich, the lead on this study is quoted as follows:

She says the difference in diets reflects the fact that the two groups lived in two very different environments.

Northern Europe, including Belgium, had wide open spaces with grasslands and many mammals. "It would have been very grassy, and kind of mountainous," says Weyrich. "You can imagine a big woolly rhino wandering through the grass there." Perhaps tracked by hungry Neanderthals looking for dinner.

But farther south in Spain, the Neanderthals lived in dense forests. "It's hard to imagine a big woolly rhino trying to wedge themselves between the trees," says Weyrich. And so, she says the Neanderthals there feasted on all kinds of plants and mushrooms. "They're very opportunistic, trying to find anything that's edible in their environment."

We are told by supposedly respectable historians that want to write a grand narrative for the human race that the human body has evolved handle a particular diet.  The very fact that humans adapted to environments from the frigid north where little green grows, to the equatorial regions, or at least environments as varied as ancient Belgian grasslands and dense Spanish forests indicates that humans were not evolved to handle any particular diet.   (Don't quibble that this study is about Neanderthals, not homo sapiens sapiens; our non-Neanderthal ancestors were more successful than the Neanderthal line, and so likely were even more adaptable than the Neanderthals.)

What is amazing is that people with a supposedly scientific temper swallow this historian nonsense with little to no skepticism.   Since I don't think we evolved to credulously believe historians, I'm not sure what is the basis for this lack of skepticism.