The quality of a lobby's argument is generally inversely proportional to their touchiness to debate. Lobbies that feel like they're on solid ground don't tend to freak out when, say, an intern somewhere writes a blog post that's skeptical of their industry. Lobbies that know they're on the wrong side of the argument but are hoping that money and intimidation can keep them afloat react with overwhelming force to even the mildest provocation -- say, an intern somewhere writing a blog post.
The American Farm Bureau is the latter type of lobby. Since it's impossible to argue that meat production isn't a major contributor to global warming, it has settled for attacking interns who dare voice this reality. Classy. And for more on meat and climate, see this article.