Unpleasant people is right!
I have been off and on vegan and vegetarian and a bodybuilder most of my life. I never notice a difference in teh amount of muscle I can build nor the amount I carry based on whether or not I am a vegetarian or vegan at the time. It all has to do with training intensity, your training program, and nutrition. Nutrition comes in many forms, as long as I get enough calories and protein...plants or meat....doesn't matter one bit. In fact science is showing us that plant sources are more bioavailable.
I don't understand where the argument is.
Where is the magic in animal protein? Are they saying it is the growth hormone effect? What's the deal?