Well, as much as vegan are extremist, they are a necessary evil, as long as people eat so much more meat than it is needed or even healthy.
I heard that you only needed 300 g of meat for a week. If you eat more, not only it isn't necessary, but it can create health issues.
Also, if the chinese would eat as much eat as the americans, they wouldn't be anough animals in the world to feed only the chineses.
As long as the average or meat eating is too high in some areas, we need other people to not eat meat or eat not enough of it...