We're falling back in the basic elements of humanity here, in all its forms. To have empathy for other living creatures is to be "humane", and when someone loses that empathy and ability to relate in an emotional way to others we classify him/her as "sick" and apply labels such as "monster" and "animal" to separate them from what we consider to be human.

To force an animal to live in an entirely vegetative state simply so we can use it for meat is distinctly lacking in empathy. We've removed all pleasures from the chicken's life, including just the simple pleasures of a good meal or the enjoyment of fine weather. Likewise, to have corrupted and engineered the mind of the pig to cause it to rush excitedly to its death is similarly sadistic. To override the most base of all instincts, which is that of survival, solely so we can have a guilt-free meal is a disturbing concept.

And finally, the man's battle with his own conscience shows him to be incredibly normal I think. We all have temptations that we may choose to avoid because we feel they are morally wrong. When the morality of it comes into question, we waver. And I think ultimately, his final hesitation was due to him acknowledging there was something wrong with the process but he can't quite put his finger on what it is. So he eats. Very human.