He compares the life of a farmed animal to a worker who has to fight traffic to spend their time working in a cubicle, but an office worker has leisure time, probably a family to spend time with, and enough money to make them willing to work at the job in the first place.
Also: very few office workers get mutilated to prevent them from mutilating their coworkers out of stress, or locked into their cubicles full-time and forced to wallow in their own faeces (periodically being hosed down from outside), or are so over-bred for meat production purposes that even in their cramped conditions the strain of their under-used, oversized muscles strains their skeletons and joints to the breaking point.
Oh, and instead of a salary designed to seem big but actually undervalue your performance, you get paid in being killed (not infrequently a painful and lingering experience) and having any children you bore taken away for no obvious reason.
Yes. “If you have doubts on this point, I suggest you visit a farm” is a massive Appeal to Generalization from One Example. I'm pretty sure some farms are a helluva much worse than others, and I strongly suspect that the farms a random person is most likely to visit will be closer to the good end of the scale.
If it's worth saying, but not worth its own post, even in Discussion, it goes here.