Despite 60 years of propaganda, Big Food and Big Pharma have failed to show ANY unhealthy intake of saturated fat and cholesterol. All plant fats are subject to oxidation and are unstable leading to metabolic diseases like CVD, diabetes and dementia. Here re the vitamins you cannot get from a plant-based diet:
Vitamin A (beta carotene is poorly converted) , B6 (Pyridoxal, Pyridoxamine), B12, D, E (Animal) F, K2, Q10. Amino acids: Creatine, Carnitine, Carnosine, and Taurine. Also Heme-iron, Collagen, Omegas: DHA, EPA, CLA, Cholesterol and Balanced, fully bioavailable Complete Protein (Consists of 9 essential amino acids)
Antinutrients & TOXINS in plants: Alkaloids, Alpha-amylases, Arsenics, Cellulose, Cyanogenic glycosides, Fiber, Flavonoids, Gluten, Lectins, Mycotoxins, Oxalates, Phenolics, Photosensitizers, Phytic acid, Salicylates, Saponins, Sulforaphane, Tannins, Glucosinolates,Terpenoids and etc. 99.99% of all pesticides in plant food are natural and found in organic produce too.
https://www.ncbi.nlm.nih.gov/pubmed/2217210What you call "appeal to history" is what rational people call "biology"
Let's look at the fitness benefits of plant-only diets:
https://www.youtube.com/watch?v=MNRHyllozUQI think "Clarification!" is in there^