I was in China for a month in the summer of 2007 (along with my older brother). ^^ It was supposedly a vacation, but more like my parents want me to be in the Chinese environment for "practicing" (can't come up with another word) my Chinese. I was mostly there just to learn a little more about the environment of the Chinese culture, except the only things I most definitely learned was the fact that 90% of the people smoke (I definitely said a couple times that I was going to die from second-hand smoke while I was there) and that clear, blue skys are ultra rare in cities. ...Changing topic... Depending on how you look at the documentaries, you can get different reactions. I watched one on the processing of pork. Some people find it cruel to gas the pigs (with CO2) to death, but on the other hand, seeing the pigs squeal to death isn't a very pretty sight either. That's just some random example I thought of. The "environmental" reasons (I'm supposing you're referring to the "animal-cruelty" stuff) are reasonable at certain times, but they aren't just going to stop because of a minute percentage of the population. There are some people who wuss out, becuase they discover where pork comes from and how its processed and gets disgusted by it. Besides, the human body needs proteins easily found in meat. People can get those same proteins and other nutrients if they knew how to balance their diets well, but meat is the easy way out. There are plenty of vegetarians (especially the single ones in a group of hungry carnivores) who become malnourished because they can't juggle the complicated non-meat diets.
Sorry for such a long reply. DX I just felt like getting it all off my chest. I really don't understand vegetarians and their justification (but I'm only a mindless freshman high school student).