Patrick is a dedicated worker for animal rights. He sees a wrong and works tirelessly to bring people's attention to it. The fact that so many horses die from these races takes a little of the glamor out of what is really a cruel spectacle: doped up animals running for their lives.
All of us have an inherent empathy for defenseless animals. We have to be trained to put these feelings aside when we exploit animals for a living. It is a little like basic training in the military, where you are trained to "kill" your fellow human being. In bayonet training we had to run down a short track and thrust our blade into a lifelike dummy, all the while yelling "kill, kill, kill." We learn to celebrate killing at the track too.