I remember when this first came out last October. The guy is plain stupid. He could have stopped that at any point my yelling at the bull or slapping it in the face (not that I really condone physical contact against wildlife unless its self-defense). More than likely it would have run off. In my opinion, the guy was just egging it on to get good photos and a "brag-about-it" experience.
I have good friends that work in the Natural Resources Department of the Grand Canyon and, every year, they have to deal with human/elk interactions because people think its cool to approach a big bull elk and get their photo taken. This, despite the big signs that say "leave the wildlife alone" and "do not approach wildlife". During the rut, its amazing more people aren't hurt up there.