Yeah this one quote from Yourofsky should at a minimum give you a moment of hesitation (or perhaps cause you to run at top speed in the other direction, and maybe call the police from your cell phone on the way) before buying into his philosophy:

"Every woman ensconced in fur should endure a rape so vicious that it scars them forever."

This kind of thinking scares the crap out of me, and is not any different than certain radicals blowing up innocent people in the name of "God".

Moving the question (and answer) further away from the radical and political and closer to nutrition, you can find various threads here on vegans and veganism and find various links about the potential nutritional impact of such a diet.

I think it might be possible for certain people to be fairly healthy on a vegan diet, if they were very careful about what they ate and had the right supplements. I personally don't think that a Paleo or meat and protein heavy diet is for everyone, and some people can live on starches and vegetables. However, there are certain essential nutrients that are absent from a vegan diet without a lot of supplements, such as vitamin B (especially B12), vitamin A and vitamin K. The diet is just a game of how to shore up what you're lacking with supplements.

The largest and most obvious drawback to a vegan diet is the lack of protein. There just aren't any good sources of it. Many vegetarians and vegans think that tofu is a good source of protein, but firm tofu is only about 10% protein, soft tofu about 5% (compared to 3.5% for cow's milk). If you believe that protein is a necessary macro-nutrient (perhaps debatable in the wide world but certainly not in Paleo circles), then this diet just doesn't make sense.

There has never been any culture or civilization that has thrived on a vegan diet (that we know of, of course). One reason might be that such a diet is only sustainable if you have a bunch of supplements and vitamins which weren't available historically. The human body just wasn't built to live on this diet.

In contrast, a majority of human cultures around the world have become so by domesticating animals. Just eating the milk and eggs of animals without harming them improves your diet by leaps and bounds, and this small change makes the difference between starvation and a sustainable diet. However, this is just too much for the vegans it seems.