I'm highly skeptical about a documentary that has "vegan" in its title. I would like to try a vegan diet at some point just for the sake of the experiment, because I like doing experiments. But skipping through the video at some point a person says that the casein protein in the milk is responsible for autism and other childhood illnesses. What a load of bullshit. When I was a kid I was drinking milk every day, and some days I'd have sheep milk and I ate a lot of cheese made from sheep milk. I don't remember having any problems from it, albeit I recognize that I'm statistically insignificant in this case.
Recently watched some speech by Neil Tyson where he used as an example a spelling competition where one kid says "Cat"(right), another says Kat(wrong), and another XGB or what(wrong). The thing is that Kat and XGB are both equally judged wrong, even if Kat is, well, less wrong. Such is with the way of most of our thinking, since we're human beings and it just gets over our heads to integrate a lot of information. My point is that one needs to inform oneself from lots of sources, without completely accepting the information as the ultimate truth and have a holistic approach on things like how to live healthy. What if I say go on and have an eskimo diet because they have low probability of having heart problems due to their omega 3&6 intake - and this by eating mostly only meat and animal fat. But there's a catch: their genetic code is different and have adapted their bodies to this diet.
In my opinion, our western lifestyle problem lies in the high doses of highly refined carbohydrates(and the worst - added sugar) combined with a sedentary lifestyle. If we're able to solve just this problem, I think we can eradicate a lot of illnesses.
Veganism is a non-satisfactory alternative for now. We don't understand enough of how our bodies work to say that veganism is the answer. I'm actually interested if we have any data about veganism over sufficient long periods at all to draw some conclusions - as is with the eskimo diet, mediteranean diet etc.