Unless they are a vegetarian / vegan . . . . they don't have a leg to stand on.
It's eco-friendly in the extreme if done properly, much closer to nature, less wasteful (by far), much more animal friendly when taken as a whole industry.
And a whole load more.
But like i said, if they are an 'anti' etc, but not a vegetarian / vegan, then they are an ignorant, hypocritical b*****d, and i usually make them feel bad about themselves. . . .