What can you say? The man likes pain.

From Slate's review of Apocalypto:

For a good hour, I tried to pretend that I had never heard of Mel Gibson: the maker of fanatical blockbusters, the spewer of hateful rants. I tried—really tried—to experience Apocalypto as an ethnographic thriller about an ancient culture. But though it may have been researched to within an inch of its life, this film is not, by any reasonable standard, ethnography. It teaches us nothing about Mayan civilization, religion, or cultural innovations. (Calendars? Hieroglyphic writing? Some of the largest pyramids on Earth?) Rather, Gibson's fascination with the Mayans seems to spring entirely from the fact (or fantasy) that they were exotic badasses who knew how to whomp the hell out of one another, old-school. You don't leave Apocalypto thinking of the decline of civilizations or the power of myth or anything much except, wow, that is one sick son of a bitch.