This is an ad hominem and quite unfair. Michael Greger states himself that he does not like the term veganism, and he also writes that it was the health benefits of a plant based diet that led him to promote that diet. To call him a "vegan animal welfare crusader" is a bit hyperbolic to say the least.
From Greger's book How Not to Die he writes in the Introduction to Part 2:
> From a nutrition standpoint, the reason I don’t like the terms vegetarian and vegan is that they are only defined by what you don’t eat. When I used to speak on college campuses, I would meet vegans who appeared to be living off french fries and beer. Vegan, technically, but not exactly health promoting. That’s why I prefer the term whole-food, plant-based nutrition. As far as I can discern, the best available balance of evidence suggests that the healthiest diet is one centered on unprocessed plant foods. On a day-today basis, the more whole plant foods and the fewer processed and animal products, the better.
And from the Preface of How Not to Die he writes:
> True, I have biases of my own to rein in. Although my original motivation was health, over the years, I’ve grown into quite the animal lover. Three cats and a dog run our household, and I’ve spent much of my professional life proudly serving the Humane Society of the United States as the charity’s public health director. So, like many people, I care about the welfare of the animals we eat, but first and foremost, I am a physician. My primary duty has always been to care for my patients, to accurately provide the best available balance of evidence.
But how are their arteries looking?
> but I have yet to run across [a vegetarian/vegan] in remission on no medication, for two years or longer, so they might be rare
How many have you run into? How strictly were they following a whole-food plant-based diet? What is your sample size?
Scientifically speaking, the movie "What The Health" summarizes the facts succinctly:
Low Fat, Plant-Based Diet is More than Twice as Powerful at Controlling and/or Reversing Diabetes, than the ADA Diet Recommending Meat and Dairy
See http://www.whatthehealthfilm.com/facts/ for a list of citations supporting that statement.