I don't think that the idea that humans ancestors could not have survived an African wild animal-only diet due to their low far content is vegan propaganda. The author believes that meat-eating was an essential step in human evolution, as stated in this paper,
https://nature.berkeley.edu/miltonlab/pdfs/meateating.pdf (which includes references to insects this time) but that the meat-eating supplemented plant-eating rather than replacing it entirely. The author also states that circumpolar peoples can survive on a virtually animal-only diet but this is because the animals they eat have a high fat content. In other words, it is possible for modern humans to live-off a mostly animal diet if those animals have sufficient fat stores. However, our ancestors on the African savannah would not have been able to do this as the local animals did not contain enough fat. Because humans have a slower gut-transit time than carnivores,they cannot eat enough low-fat animal produce in a day to supply all their calories. I don't think the author mentions 'rabbit starvation' but I would have though that phenomenon would be another problem.
https://en.wikipedia.org/wiki/Protein_poisoning
The reason that the author talked about eating more fruit and veg rather than less carbs and processed food is that she was specifically replying to Cordain et al who were advocating increased consumption of animal foods based on hunter-gatherer diets. Whole foods versus processed foods would be a different debate.
You don't have the digestive system typical of a carnivore (large canines, simple gut, fast transit time) but I assume you cope with your diet by use of tools (such as a knife), cooking and by eating domesticated animals that have been bred for a high fat content. (In contrast,the Giant Panda has the digestive system of a carnivore but eats a 100% plant-based diet. The way it copes with this is to spend virtually all day eating and doing not much else.) I suspect the people where you live, if they survived off an all-meat diet, would have included some fatty meat in their diet such as beaver, goose or fish. Unless you live very far north, it is likely that there was also some carbohydrate consumption from gathered berries and leaves.
At the end of the day, there isn't enough planet for all human beings to eat an animal-only diet, even if it was desirable to do so.